A rescue worker holds an injured boy after what activists said were airstrikes carried out by the Russian air force in Idlib city, Syria December 20, 2015. (Photo by Ammar Abdullah/Reuters)

Tajammu Al-Ezza brigade fighters react while firing a Grad shell towards forces of Syria's President Bashar Al-Assad stationed in Salhab village, Hama countryside, May 7, 2015. (Photo by Mohamad Bayoush/Reuters)

Syrian girls carry bags with bread as people queue up outisde a bakery in a rebel held neighbourhood in the northern city of Aleppo on July 12, 2016. Since mid-2012, Aleppo has been roughly divided between government control in the west and rebel control in the east, and has suffered enormous destruction in the war that has killed more than 280,000 people nationwide. Last week, a government advance brought regime troops within firing range of the Castello Road, the only remaining supply route into the opposition-held east, effectively severing rebel neighbourhoods from the outside world. With their route to the outside world cut, there is no new flour coming to the city's bakeries, and fuel to light their ovens is also now hard to find. (Photo by Karam Al-Masri/AFP Photo)

Rebel fighters fire towards positions of regime forces in Ramussa on the southwestern edges of Syria's northern city of Aleppo on August 6, 2016. Syrian rebels said they have broken a three-week government siege of second city Aleppo, turning the tables on Russian-backed regime forces who are now on the defensive. (Photo by Fadi Al-Halabi/AFP Photo)

Militant Islamist fighters take part in a military parade along the streets of Syria's northern Raqqa province June 30, 2014. The fighters held the parade to celebrate their declaration of an Islamic “caliphate” after the group captured territory in neighbouring Iraq, a monitoring service said. The Islamic State, an al Qaeda offshoot previously known as Islamic State in Iraq and the Levant (ISIL), posted pictures online on Sunday of people waving black flags from cars and holding guns in the air, the SITE monitoring service said. (Photo by Reuters/Stringer)

A grave cleaner holds up a skull during exhumation works at the Cemetery General in Guatemala City May 24, 2013. If a lease on a grave has expired or not been paid, grave cleaners will break open the crypts to remove and rebury the bodies. (Photo by Jorge Dan Lopez/Reuters)

Dogs of a visitor pass by the grave of Marquise and Tony, the two small dogs of the Princess Lobanoff de Rostoff at the cimetiere des chiens (Cemetery of dogs) ahead of the commemoration of All Saints Day at the Montmartre cemetery in Asnieres, northern Paris, France, October 30, 2016. (Photo by Charles Platiau/Reuters)

WWII veterans attend a ceremony to place tobacco pouches of soil from WWII mass graves of Red Army soldiers abroad, in the custody of the Central Armed Forces Museum in Moscow, Russia on March 6, 2020. The grave soil has been brought from Abkhazia, Germany, Kyrgyzstan, US, Ukraine, France, Estonia, Mongolia, Bulgaria, UK, Uzbekistan and South Ossetia. (Photo by Alexander Shcherbak/TASS)