At least 12 children and an adult were killed by a Russian airstrike at a school in northern Syria Monday.
Dozens more children and their teachers were injured, according to the British-based Syrian Observatory for Human Rights (SOHR).
Photos released on social media show toppled desks covered in dust and rubble and bolder-sized pieces of a partially collapsed building lying beneath a gaping hole. In video footage reportedly released by members of the resistance movement, one child recounted how her class was set to take an examination when the airstrike occurred.
The scene of chaos highlights lingering questions about collateral damage on all sides of the years-long civil war.
The strike took place in the town of Anjara, about nine miles outside the city of Aleppo, a region that has seen an escalation in fighting in recent days by pro-government forces and the rebel militias opposing them.
Russia began to carry out airstrikes in September, though observers say its forces have mostly struck rebel targets attempting to oust President Bashar al-Assad, a long-time Russian ally.
According to SOHR, Russia has killed more than 2,300 people, about 800 of them civilians. More than 250,000 have died on both sides of bloody conflict.
In early December, the main opposition bloc, the Syrian National Coalition (SNC), said Russian airstrikes had killed 1,730 civilians and have mainly targeted groups fighting the Syrian government. SNC recently called on the United Nations to intervene against Russia.
"Nearly 94 percent of the 12,000 sorties the Russian Air Force has so far flown in Syria targeted civilians and the Free Syrian Army," a statement released by the group said.
More than 260 civilians have been killed by US-led coalition airstrikes, according to SOHR. The alliance has conducted 9,000 airstrikes during the last 18 months, dropping 32,000 bombs.
“The US has indeed been successful in minimizing civilian harm in its airstrikes against [Islamic State], and should continue to take precautions even as they intensify airstrikes,” said Federico Borello, the executive director of the Center for Civilians in Conflict, an advocacy group, The New York Times reported.
The number of airstrikes picked up after the attacks on Paris in November, a month that alone saw more than 3,000 strikes against Islamic State, which controls significant territory in Iraq and Syria.
In November, the United States began Operation Inherent Resolve, a 17-country coalition against Islamic State.
The UN children’s fund UNICEF told Reuters on Monday it was looking into the Russian strike. Human rights groups say Russia routinely targets residential areas, a claim the country’s government denies.