China has developed supersonic anti-ship cruise missiles while the U.S. rely on cold-war era subsonic Harpoon missiles.

Ukrainian border guards check cars at a checkpoint at the contact line between pro-Russian rebels and Ukrainian troops in Mayorsk, Ukraine, February 25, 2019. More than a million people cross the 500 km contact line every year, many of them are pensioners who spend hours queuing, in cold, heat, rain or snow, as they rely on state benefits that can only be obtained on the government-controlled side. REUTERS/Gleb Garanich SEARCH "ELECTION WAR" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Ukrainian border guard checks a car at a checkpoint at the contact line between pro-Russian rebels and Ukrainian troops in Mayorsk, Ukraine February 25, 2019. More than a million people cross the 500 km contact line every year, many of them are pensioners who spend hours queuing, in cold, heat, rain or snow, as they rely on state benefits that can only be obtained on the government-controlled side. REUTERS/Gleb Garanich SEARCH "ELECTION WAR" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

People line up as border guards check their luggage before they go through passport control, after crossing the contact line between pro-Russian rebels and Ukrainian troops in Mayorsk, Ukraine, February 25, 2019. More than a million people cross the 500 km contact line every year, many of them are pensioners who spend hours queuing, in cold, heat, rain or snow, as they rely on state benefits that can only be obtained on the government-controlled side. REUTERS/Gleb Garanich SEARCH "ELECTION WAR" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Ukrainian border guards walk past a mine-warning sign near the contact line between pro-Russian rebels and Ukrainian troops in Mayorsk, Ukraine, February 25, 2019. More than a million people cross the 500 km contact line every year, many of them are pensioners who spend hours queuing, in cold, heat, rain or snow, as they rely on state benefits that can only be obtained on the government-controlled side. The sign in Russian reads: "Don't leave the road. The area along the road is mined." REUTERS/Gleb Garanich SEARCH "ELECTION WAR" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Ukrainian border guards wave at cars to go through at a checkpoint at the contact line between pro-Russian rebels and Ukrainian troops in Mayorsk, Ukraine February 25, 2019. More than a million people cross the 500 km contact line every year, many of them are pensioners who spend hours queuing, in cold, heat, rain or snow, as they rely on state benefits that can only be obtained on the government-controlled side. REUTERS/Gleb Garanich SEARCH "ELECTION WAR" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

People line up as they wait at passport control after crossing the contact line between pro-Russian rebels and Ukrainian troops in Mayorsk, Ukraine, February 25, 2019. More than a million people cross the 500 km contact line every year, many of them are pensioners who spend hours queuing, in cold, heat, rain or snow, as they rely on state benefits that can only be obtained on the government-controlled side. REUTERS/Gleb Garanich SEARCH "ELECTION WAR" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

A girl looks out of a bus window which crosses the contact line between pro-Russian rebels and Ukrainian troops as Ukrainian border guard stands by in Mayorsk, Ukraine, February 25, 2019. More than a million people cross the 500 km contact line every year, many of them are pensioners who spend hours queuing, in cold, heat, rain or snow, as they rely on state benefits that can only be obtained on the government-controlled side. REUTERS/Gleb Garanich SEARCH "ELECTION WAR" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Nominees for the Foreign Language Film category, Florian Henckel von Donnersmarck, director of film "Never Look Away" - Germany, Alfonso Cuaron, director of film "Roma" - Mexico, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, react during a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Alfonso Cuaron, director of film "Roma" - Mexico, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, attend a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Pawel Pawlikowski, director of film "Cold War" - Poland and Hirokazu Kore-eda, director of film "Shoplifters" - Japan talk during a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Florian Henckel von Donnersmarck, director of film "Never Look Away" - Germany, Alfonso Cuaron, director of film "Roma" - Mexico, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, attend a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Florian Henckel von Donnersmarck, director of film "Never Look Away" - Germany, Alfonso Cuaron, director of film "Roma" - Mexico, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, attend a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Florian Henckel von Donnersmarck, director of film "Never Look Away" - Germany, Alfonso Cuaron, director of film "Roma" - Mexico, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, attend a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Florian Henckel von Donnersmarck, director of film "Never Look Away" - Germany, Alfonso Cuaron, director of film "Roma" - Mexico, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, attend a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Florian Henckel von Donnersmarck, director of film "Never Look Away" - Germany, Alfonso Cuaron, director of film "Roma" - Mexico, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, attend a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, attend a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Nominees for the Foreign Language Film category, Pawel Pawlikowski, director of film "Cold War" - Poland, Hirokazu Kore-eda, director of film "Shoplifters" - Japan and Nadine Labaki, director of "Caparnaum" - Lebanon, attend a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Pawel Pawlikowski, director of film "Cold War" - Poland, a nominee for the Foreign Language Film category, attends a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Pawel Pawlikowski, director of film "Cold War" - Poland, a nominee for the Foreign Language Film category, attends a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Pawel Pawlikowski, director of film "Cold War" - Poland, a nominee for the Foreign Language Film category, attends a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

Pawel Pawlikowski, director of film "Cold War" - Poland, a nominee for the Foreign Language Film category, attends a pre Oscar reception ahead of the 91st Academy Awards, in Beverly Hills, California February 21, 2019. REUTERS/Mario Anzuoni

A woman reads a Cold War timeline during a tour of the 103-foot Titan II Intercontinental Ballistic Missile (ICBM) site which was decommissioned in 1982, at the Titan Missile Museum in Sahuarita, Arizona, U.S., February 2, 2019. REUTERS/Nicole Neri

Tom Pollock and Helen Pollock read a Cold War timeline during a tour of the 103-foot Titan II Intercontinental Ballistic Missile (ICBM) site which was decommissioned in 1982, at the Titan Missile Museum in Sahuarita, Arizona, U.S., February 2, 2019. REUTERS/Nicole Neri

Snow covers the Lebanese border town of Arsal, Lebanon January 9, 2019. REUTERS/Zeina Alhoujeyri

Cubans read the draft proposal of changes to the constitution during the beginning of a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo TPX IMAGES OF THE DAY

Cubans attend a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Cubans attend a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Cubans attend a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Cubans read the draft proposal of changes to the constitution during the beginning of a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Cubans read the draft proposal of changes to the constitution during the beginning of a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Cubans attend a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Cuban General Samuel Rodiles Planas speaks during a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Cuban General Samuel Rodiles Planas speaks during a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Former Cuban cosmonaut and military officer Arnaldo Tamayo speaks during a public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

A Cuban nurse reads the draft proposal of changes to the constitution during the beginning of a public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo?

A Cuban nurse fans herself before the beginning of a public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

Cubans attend the beginning of a public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo?

A Cuban looks on as she waits for the beginning of a public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

A Cuban nurse holds the draft proposal of changes to the constitution during the beginning of a public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

A general view shows the public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

A man is silhouetted near a picture of late Cuban President Fidel Castro before the beginning of the public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

A Cuban reads the draft proposal of changes to the constitution during the beginning of a public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

A Cuban walks past a billboard promoting the public political discussion to revamp a Cold War-era constitution in Havana, Cuba August 10, 2018. Picture taken August 10, 2018. REUTERS/Tomas Bravo

A young Cuban checks his phone before the beginning of a public political discussion to revamp a Cold War-era constitution at the Nguyen Van Troi Polyclinic in Havana, Cuba August 13, 2018. REUTERS/Tomas Bravo

A woman displays the set list given to her by Cold War Kids band after their performance on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. Picture taken June 15, 2018 REUTERS/Mark Makela

A worker with shredded jeans collects refuse after Cold War Kids on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. Picture taken June 15, 2018. REUTERS/Mark Makela

Revelers listen to Cold War Kids perform on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. Picture taken June 15, 2018. REUTERS/Mark Makela

A woman dances as Cold War Kids perform on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. Picture taken June 15, 2018. REUTERS/Mark Makela

A woman watches Cold War Kids perform on the second day of the Firefly Music Festival in Dover, Delaware U.S., June 15, 2018. Picture taken June 15, 2018. REUTERS/Mark Makela

Cold War Kids perform on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. REUTERS/Mark Makela

Cold War Kids perform on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. Picture taken June 15, 2018. REUTERS/Mark Makela

Revelers dance to Cold War Kids on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. Picture taken June 15, 2018. REUTERS/Mark Makela

Revelers dance to Cold War Kids on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. Picture taken June 15, 2018. REUTERS/Mark Makela

A reveler holds an inflatable heart as Cold War Kids perform on the second day of the Firefly Music Festival in Dover, Delaware, U.S., June 15, 2018. Picture taken June 15, 2018. REUTERS/Mark Makela

Assessing the capability of North Korean Cold War-era artillery and its danger to Seoul