French President Emmanuel Macron speaks with Italy's Prime Minister Mario Draghi and Poland's Prime Minister Mateusz Morawiecki during the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

Heads of State and Government attend the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

Portugal's Prime Minister Antonio Costa speaks with Hungary's Prime Minister Viktor Orban and Italy's Prime Minister Mario Draghi during an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

European Commission Executive Vice-President for An Economy that Works for People Valdis Dombrovskis, European Parliament President David Sassoli and Sweden's Prime Minister Stefan Lofven take part in a panel discussion at an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

French President Emmanuel Macron fist bumps Poland's Prime Minister Mateusz Morawiecki during the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

Sweden's Prime Minister Stefan Lofven takes off his protective face mask as he prepares to speak during the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

European Commission President Ursula von der Leyen speaks during the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

European Commission President Ursula von der Leyen and Portugal's Prime Minister Antonio Costa arrive for the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

Portugal's Prime Minister Antonio Costa speaks during the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

Portugal's Prime Minister Antonio Costa speaks during the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

European Commission President Ursula von der Leyen speaks during the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

French President Emmanuel Macron speaks with Spain's Prime Minister Pedro Sanchez during the opening ceremony of an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Luis Vieira/Pool via REUTERS

European Commissioner for Europe fit for the Digital Age, Margrethe Vestager, arrives for an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Jose Coelho/Pool via REUTERS

Slovenia's Prime Minister Janez Jansa arrives for an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Jose Coelho/Pool via REUTERS

European Commissioner for Europe fit for the Digital Age, Margrethe Vestager, speaks to the media as she arrives for an EU summit at the Alfandega do Porto Congress Center in Porto, Portugal May 7, 2021. Francisco Seco/Pool via REUTERS

Leon Small holds his hand over his heart as he recites the pledge of allegiance during a citizenship ceremony in New York City, New York, U.S., April 28, 2021. REUTERS/Carlo Allegri

An aerial view shows domestic waste floating on the stream of the Citarum river in Bandung, Indonesia, March 15, 2021. The government has pledged to clean the Citarum river, considered among the world's most polluted, and make the water there drinkable by 2025, but household and industrial waste have continued to flow in its stream. Picture taken with a drone. REUTERS/Willy Kurniawan SEARCH "GLOBAL WATER" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES

U.S. President-elect Joe Biden and his spouse Jill Biden listen to the Pledge of Allegiance during his inauguration as the 46th President of the United States on the West Front of the U.S. Capitol in Washington, U.S., January 20, 2021. REUTERS/Jonathan Ernst/Pool

Capt. Andrea Hall of the city of South Fulton deliveres the pledge of allegiance during the 59th Presidential Inauguration at the U.S. Capitol in Washington, U.S., January 20, 2021. Erin Schaff/Pool via REUTERS

Members of the Michigan House of Representatives say the Pledge of Allegiance amid stricter security at the state Capitol in Lansing, Michigan, U.S. January 13, 2021, the first day the state legislature was back in session since the open carry of firearms in the building was banned. REUTERS/Michael Martina

Attendees put their hands over their hearts during the pledge of allegience at a press conference on election results with attorneys Sidney Powell and L. Lin Wood in Alpharetta, Georgia, U.S., December 2, 2020. REUTERS/Elijah Nouvelage

A supporter of U.S. President Donald Trump holds a banner while reciting the Pledge of Allegiance during a "Stop the Steal" protest after the 2020 U.S. presidential election was called for Democratic candidate Joe Biden, in Washington, U.S. November 14, 2020. REUTERS/Jim Urquhart

General view shows the University of Cambridge, as it pledges to reduce the climate-warming emissions from its investments to net zero by 2038, in Cambridge, Britain, October 1, 2020. REUTERS/Matthew Childs

General view shows the University of Cambridge, as it pledges to reduce the climate-warming emissions from its investments to net zero by 2038, in Cambridge, Britain, October 1, 2020. REUTERS/Matthew Childs

General view shows the University of Cambridge, as it pledges to reduce the climate-warming emissions from its investments to net zero by 2038, in Cambridge, Britain, October 1, 2020. REUTERS/Matthew Childs

General view shows the University of Cambridge, as it pledges to reduce the climate-warming emissions from its investments to net zero by 2038, in Cambridge, Britain, October 1, 2020. REUTERS/Matthew Childs

General view shows the University of Cambridge, as it pledges to reduce the climate-warming emissions from its investments to net zero by 2038, in Cambridge, Britain, October 1, 2020. REUTERS/Matthew Childs

General view shows the University of Cambridge, as it pledges to reduce the climate-warming emissions from its investments to net zero by 2038, in Cambridge, Britain, October 1, 2020. REUTERS/Matthew Childs

General view shows the University of Cambridge, as it pledges to reduce the climate-warming emissions from its investments to net zero by 2038, in Cambridge, Britain, October 1, 2020. REUTERS/Matthew Childs

A man holds a hand over his heart for the U.S. Pledge of Allegiance during a rally of the far right group Proud Boys, in Portland, Oregon, U.S., September 26, 2020. REUTERS/Leah Millis

The overflow crowd of supporters stands for the U.S. Pledge of Allegiance before a campaign rally with U.S. President Donald Trump in Londonderry, New Hampshire, U.S., August 28, 2020. REUTERS/Brian Snyder

Cedric Richmond, Jr., son of U.S. Rep Cedric Richmond (D-LA), leads the U.S. Pledge of Allegiance during the 4th and final night of the 2020 Democratic National Convention, as participants from across the country are hosted over video links from the originally planned site of the convention in Milwaukee, Wisconsin, U.S. August 20, 2020. 2020 Democratic National Convention/Pool via REUTERS

Cedric Richmond, Jr., son of U.S. Rep Cedric Richmond (D-LA), leads the U.S. Pledge of Allegiance during the 4th and final night of the 2020 Democratic National Convention, as participants from across the country are hosted over video links from the originally planned site of the convention in Milwaukee, Wisconsin, U.S. August 20, 2020. 2020 Democratic National Convention/Pool via REUTERS

The U.S. Pledge of Allegiance is seen carved behind the statues of Confederates Kirby Smith (L) and James George outside the Congressional Auditorium in the U.S. Capitol in Washington, U.S. July 23, 2020. The House recently voted to remove statues of Confederates in the Capitol. Picture taken July 23, 2020. REUTERS/Erin Scott

French police apprehend a topless woman who protests in front the Elysee Palace before the first weekly cabinet meeting of the new French government in Paris, France, July 7, 2020. The slogan reads " RIP the pledges". REUTERS/Benoit Tessier

French police apprehend a topless woman who protests in front the Elysee Palace before the first weekly cabinet meeting of the new French government in Paris, France, July 7, 2020. The slogan reads " RIP the pledges". REUTERS/Benoit Tessier

Joe Biden has enough pledged delegates to be the official nominee after Democratic primary on June 9.

Workers at Sunbelievable tanning salon say the U.S. Pledge of Allegiance just before owner Bobby Catone opens his business against local health recommendations and a shut down order, during the outbreak of the coronavirus disease (COVID-19), in the Staten Island borough of New York, U.S., May 28, 2020. REUTERS/Brendan McDermid

Supporters of U.S. President Donald Trump and others participate in the Pledge of Allegiance during a protest against coronavirus disease (COVID-19) restrictions outside the Pennsylvania State Capitol in Harrisburg, Pennsylvania, U.S., May 15, 2020. REUTERS/Jonathan Ernst

Supporters of U.S. President Donald Trump and others hold their hands over their hearts for the U.S. Pledge of Allegiance as they protest against coronavirus disease (COVID-19) restrictions during a demonstration outside the Pennsylvania State Capitol Building in Harrisburg, Pennsylvania, U.S., May 15, 2020. REUTERS/Jonathan Ernst

Attendees ay the Pledge of Allegiance as demonstrators participate in a Reopen Delaware rally against government mandated closures and calling for the reopening of the state of Delaware amid the coronavirus disease (COVID-19) pandemic at the state capitol in Dover, Delaware, U.S., May 1, 2020. REUTERS/Jonathan Ernst

Senators stand for the pledge of allegiance before the vote on the extension of Governor Gretchen Whitmer's emergency declaration/stay-at-home order due to the coronavirus disease (COVID-19) outbreak, in Lansing, Michigan, U.S. April 30, 2020. REUTERS/Seth Herald

Supporters of U.S. President Donald Trump stand for the Pledge of Allegiance during his campaign rally in Las Vegas, Nevada, U.S., February 21, 2020. REUTERS/Shannon Stapleton

Supporters of U.S. President Donald Trump stand for the Pledge of Allegiance during his campaign rally in Las Vegas, Nevada, U.S., February 21, 2020. REUTERS/Shannon Stapleton

Graduates raise their hands as take their pledge during the Hope for Prisoners Graduation Ceremony attended by U.S. President Donald Trump in Las Vegas, Nevada, February 20, 2020. REUTERS/Kevin Lamarque

Thae Yong-Ho, North Korea's former deputy ambassador to Britain,? pledges allegiance to the Korean national flag during the launching ceremony of their political party South-North Unification Party, ahead of the country's general election in April, in Seoul, South Korea, February 18, 2020. REUTERS/Heo Ran

Voters recite the Pledge of Allegiance as they attend a campaign event for Democratic 2020 U.S. presidential candidate and former Vice President Joe Biden in Waukee, Iowa, U.S., January 30, 2020. REUTERS/Mike Segar

Supporters recite the Pledge of Allegiance during a campaign event for Democratic 2020 U.S. presidential candidate and former Vice President Joe Biden in Ankeny, Iowa, U.S., January 25, 2020. REUTERS/Carlos Barria

Anti-abortion demonstrators recite the Pledge of Allegiance at a rally before the start of the March For Life on the National Mall in Washington, U.S., January 24, 2020. REUTERS/Mary F. Calvert

People arrive to attend the Pledging Conference of the Green Climate Fund (GCF) for the First Replenishment in Paris, France, October 25, 2019. REUTERS/Pascal Rossignol

French Finance Minister Bruno Le Maire delivers a speech during the Pledging Conference of the Green Climate Fund (GCF) for the First Replenishment in Paris, France, October 25, 2019. REUTERS/Pascal Rossignol

French Finance Minister Bruno Le Maire, and Green Climate Fund's Executive Director Yannick Glemarec pose for a family photo with governments delegates during the Pledging Conference of the Green Climate Fund (GCF) for the First Replenishment in Paris, France, October 25, 2019. REUTERS/Pascal Rossignol

French Finance Minister Bruno Le Maire, and Green Climate Fund's Executive Director Yannick Glemarec pose for a family photo with governments delegates during the Pledging Conference of the Green Climate Fund (GCF) for the First Replenishment in Paris, France, October 25, 2019. REUTERS/Pascal Rossignol

French Finance Minister Bruno Le Maire delivers a speech during the Pledging Conference of the Green Climate Fund (GCF) for the First Replenishment in Paris, France, October 25, 2019. REUTERS/Pascal Rossignol

French Finance Minister Bruno Le Maire delivers a speech during the Pledging Conference of the Green Climate Fund (GCF) for the First Replenishment in Paris, France, October 25, 2019. REUTERS/Pascal Rossignol

French Finance Minister Bruno Le Maire delivers a speech during the Pledging Conference of the Green Climate Fund (GCF) for the First Replenishment in Paris, France, October 25, 2019. REUTERS/Pascal Rossignol