A 10-story residential building in Belgorod, Russia, was struck overnight by a Ukrainian missile, a local governor said.
The number of those who died has increased to 15 people, according to an update from the Emergency Situations Ministry on Sunday.
"The Belgorod city and the Belgorod district came under a massive attack by the Ukrainian Armed Forces," Vyacheslav Gladkov, governor of the Belgorod region, said in a post on Telegram.
The Ukrainian Tochka-U missile that struck the building was among several that Ukraine launched overnight, the Russian Ministry of Defense said in a statement. It was unclear if the missile struck the building as a target or if the damage was caused by fragments of a downed missile, the ministry said.
Search-and-rescue workers initially recovered the bodies of 11 people from the rubble of the apartment building, according to Russia's Emergency Situations Ministry.
Ukrainian military officials did not immediately comment on the claims, which could not immediately be verified.
A central portion of the apartment building in Kharkovskaya Gora appeared in photos to have been completely destroyed, with the remaining building standing on either side of a gap.
ABC News' Dragana Jovanovic and Helena Skinner contributed to this report.