Israeli police stand inside a bomb shelter as sirens sound warning of incoming rockets launched from the Gaza Strip, in Ashkelon, southern Israel May 11, 2021. REUTERS/Amir Cohen

An Israeli police bomb disposal expert holds the remain of a rocket launched from the Gaza Strip after it landed in Ashkelon, southern Israel May 11, 2021. REUTERS/Amir Cohen

People gather outside the Polish Supreme Court after a bomb threat in Warsaw, Poland May 11, 2021. The court's Civil Chamber is due to issue guidance on Swiss francs mortgages today. REUTERS/Kacper Pempel

People walk outside the Polish Supreme Court after a bomb threat, the day the court's Civil Chamber is due to issue guidance on Swiss francs mortgages, in Warsaw, Poland May 11, 2021. REUTERS/Kacper Pempel

Firefighters wait outside the Polish Supreme Court after a bomb threat, the day the court's Civil Chamber is due to issue guidance on Swiss francs mortgages, in Warsaw, Poland May 11, 2021. REUTERS/Kacper Pempel

Police officers chat outside the Polish Supreme Court after a bomb threat, the day the court's Civil Chamber is due to issue guidance on Swiss francs mortgages, in Warsaw, Poland May 11, 2021. REUTERS/Kacper Pempel

Fire truck is pictured outside the Polish Supreme Court after a bomb threat, the day the court's Civil Chamber is due to issue guidance on Swiss francs mortgages, in Warsaw, Poland May 11, 2021. REUTERS/Kacper Pempel

An Israeli police bomb disposal expert looks out from the window of a residential building that was damaged after it was hit by a rocket launched from the Gaza Strip, in Ashkelon, southern Israel May 11, 2021. REUTERS/Amir Cohen

An Israeli police bomb disposal expert looks out from the window of a residential building that was damaged after it was hit by a rocket launched from the Gaza Strip, in Ashkelon, southern Israel May 11, 2021. REUTERS/Amir Cohen

Belgian lawyer Dimitri de Beco, representing Iranian diplomat Assadollah Assadi who was charged in Belgium with planning to bomb a meeting of an exiled Iranian opposition group in France, speaks to the media outside a court building in Antwerp, Belgium May 5, 2021. REUTERS/Clement Rossignol

Belgian lawyer Dimitri de Beco, representing Iranian diplomat Assadollah Assadi who was charged in Belgium with planning to bomb a meeting of an exiled Iranian opposition group in France, speaks to the media outside a court building in Antwerp, Belgium May 5, 2021. REUTERS/Clement Rossignol

An Afghan man looks on through a broken window after last night's car bomb blast, in Logar province, Afghanistan May 1, 2021. REUTERS/Stringer NO RESALES. NO ARCHIVES

A wounded man transferred from Logar province after a bomb blast receives treatment at a hospital in Kabul, Afghanistan May, 1, 2021. REUTERS/Omar Sobhani

A wounded man transferred from Logar province after a bomb blast receives treatment at a hospital in Kabul, Afghanistan May, 1, 2021. REUTERS/Omar Sobhani

A wounded man transferred from Logar province after a bomb blast lies in bed at a hospital in Kabul, Afghanistan May, 1, 2021. REUTERS/Omar Sobhani

A wounded man transferred from Logar province after a bomb blast receives treatment at a hospital in Kabul, Afghanistan May, 1, 2021. REUTERS/Omar Sobhani

Survivors of the bombing of Guernica Cruzita Etxabe, 92, and Paco Garcia, 93, talk to Basque premier Inigo Urkullu and mayor Jose Maria Gorrono on the 84th anniversary of the attack on the Basque town during the Spanish Civil War, in Guernica, Spain, April 26, 2021. REUTERS/Vincent West

Survivors of the bombing of Guernica, Cruzita Etxabe, 92, and Paco Garcia, 93, talk on the 85th anniversary of the attack on the Basque town by the Nazi German unit Condor Legion during the Spanish Civil War, in Guernica, Spain, April 26, 2021. REUTERS/Vincent West

A woman holds a colour smoke bomb during an anti-lockdown 'Unite for Freedom' protest, in London, Britain, April 24, 2021. REUTERS/Toby Melville

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Cooks from Euskal Gozogileak (Basque confectioners) create a full-sized reproduction of Picasso's Guernica made with chocolate, ahead of the 85th anniversary of the bombing of the town, in Lezo, Spain, April 20, 2021. Picture taken April 20, 2021. REUTERS/Vincent West

Family members look at the grave of one victim of April 21's Easter Sunday bomb attack in 2019, next to St. Sebastian's Church, one of the attacked churches, during the second anniversary, in Katuwapitiya, Sri Lanka, April 21, 2021. REUTERS/Dinuka Liyanawatte

Mass grave of the victims of April 21's Easter Sunday bomb attack in 2019 is pictured on the second anniversary, in Katuwapitiya, Sri Lanka, April 21, 2021. REUTERS/Dinuka Liyanawatte

A family member kisses the grave of one victim of April 21's Easter Sunday bomb attack in 2019, next to St. Sebastian's Church, one of the attacked churches, during the second anniversary, in Katuwapitiya, Sri Lanka, April 21, 2021. REUTERS/Dinuka Liyanawatte

Catholic priests and nuns march while holding images of the victims of April 21's Easter Sunday bomb attack in 2019, next to St. Sebastian's Church, one of the attacked churches, during the second anniversary, in Katuwapitiya, Sri Lanka, April 21, 2021. REUTERS/Dinuka Liyanawatte

Catholic priests and nuns march while holding images of the victims of April 21's Easter Sunday bomb attack in 2019, next to St. Sebastian's Church, one of the attacked churches, during the second anniversary, in Katuwapitiya, Sri Lanka, April 21, 2021. REUTERS/Dinuka Liyanawatte

A family member of one victim of the 2019 Easter Sunday bomb attacks reacts near a mass graveyard, next to St. Sebastian's Church, one of the attacked churches, during the second anniversary in Katuwapitiya, Sri Lanka, April 21, 2021. REUTERS/Dinuka Liyanawatte

Afghans remove broken glass and pieces of roof from a mosque near the site of a suicide bomb blast in Kabul, Afghanistan April 21, 2021. REUTERS/Omar Sobhani

An Afghan woman walks past the damaged windows of house after a suicide bomb blast in Kabul, Afghanistan April 21, 2021. REUTERS/Omar Sobhani

Afghans remove broken glass from a window of their house near the site of a suicide bomb blast in Kabul, Afghanistan April 21, 2021. REUTERS/Omar Sobhani

Afghan men walk past from the site of a suicide bomb attack in Kabul, Afghanistan April 21, 2021. REUTERS/Omar Sobhani

An Afghan man works on an electricity pole which was broken after a suicide bomb attack in Kabul, Afghanistan April 21, 2021. REUTERS/Omar Sobhani

Survivors Joselyn Perez and her mother Sara Valverde Perez hug with their family at the site and the moment of the first bomb blast on the anniversary of the 2013 Boston Marathon bombings in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Survivors Joselyn Perez and her mother Sara Valverde Perez hug with their family at the site and the moment of the first bomb blast on the anniversary of the 2013 Boston Marathon bombings in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Survivors Joselyn Perez and her mother Sara Valverde Perez hug with their family at the site and the moment of the first bomb blast on the anniversary of the 2013 Boston Marathon bombings in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

A man bows his head at the site and the moment of the first bomb blast on the anniversary of the 2013 Boston Marathon bombings in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Boston Mayor Kim Janey and Boston Athletic Association CEO Tom Grilk (rear) stand at a memorial to the victims of the 2013 Boston Marathon bombings on the anniversary of the attack in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Boston Mayor Kim Janey (R) and Boston Athletic Association CEO Tom Grilk stand at a memorial to the victims of the 2013 Boston Marathon bombings on the anniversary of the attack in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Chris Loper leaves flowers at a memorial to the victims of the 2013 Boston Marathon bombings on the anniversary of the attack in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Boston Mayor Kim Janey (R) and Boston Athletic Association CEO Tom Grilk stand at a memorial to the victims of the 2013 Boston Marathon bombings on the anniversary of the attack in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Melissa Belovich, who plans to run the race this year, holds a commemorative pin at the finish line on the anniversary of the 2013 Boston Marathon bombings in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Dan Soleau, who was in the finish line crowd, leaves flowers at a memorial to the victims of the 2013 Boston Marathon bombings on the anniversary of the attack in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Dan Soleau, who was in the finish line crowd, leaves flowers at a memorial to the victims of the 2013 Boston Marathon bombings on the anniversary of the attack in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Jeff Schatz and Will Belezos re-paint the finish line on the anniversary of the 2013 Boston Marathon bombings in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Jeff Schatz and Will Belezos re-paint the finish line on the anniversary of the 2013 Boston Marathon bombings in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Workers re-paint the finish line on the anniversary of the 2013 Boston Marathon bombings in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder

Mementos are left at a memorial to the victims of the 2013 Boston Marathon bombings on the anniversary of the attack in Boston, Massachusetts, U.S., April 15, 2021. REUTERS/Brian Snyder