Ammunition was likely being stored in a Russian-held school building near Donetsk during a Dec. 31 Ukrainian strike that killed almost 90 occupying troops.
The building, which had been converted for military use, was leveled, British officials said Wednesday.
“Given the extent of the damage, there is a realistic possibility that ammunition was being stored near to troop accommodation, which detonated during the strike creating secondary explosions,” British military intelligence officials said on their Twitter page.
Donetsk is in eastern Ukraine. The building was about 8 miles from the front line, one of the most intensely contested areas of the war.