There has not yet been confirmation from the Ukrainian side.
Ukraine has been defending itself against the Russian invasion for almost 1,000 days.
Russian jets, ammunition depots and fuel supplies have been hit.
“Russia’s casualty rate will likely continue to average above 1,000 a day over the next two months as Russia continues to try to overmatch Ukrainian positions,” it said.
“That’s what I stand for as chancellor.’’
The development raises questions about the fate of U.S. installations in the country following a withdrawal.
Russia’s ambassador to the U.S., Anatoly Antonov, condemned the accusations and called them “odious and unsubstantiated.”
Ukraine’s army says it is continuing its counteroffensive around Klishchiivka in eastern Ukraine after announcing its forces have recaptured the key village.
Three neighbours, including a teenager, who rushed to help, were also injured.
Ms Gamba described the use of schools both by armed forces and armed groups as “a very worrisome trend”, calling for them to remain “zones of peace”.
