At least three people were killed and dozens of residential buildings damaged in the Russian city of Belgorod near the Ukraine border, the regional governor said, after reports of several blasts in the city.

At least 11 apartment buildings and 39 private houses were damaged, including five that were destroyed, Governor Vyacheslav Gladkov posted on the Telegram messaging app.

Gladkov said earlier the “incident” was being investigated, adding, “Presumably, the air defense system worked.”

At least four people were injured and two hospitalized, including a 10-year-old boy, Gladkov said.

Reuters could not independently verify the reports. There was no immediate reaction from Ukraine to the reports.

Belgorod, a city of nearly 400,000 some 40 km (25 miles) north of the border with Ukraine, is the administrative center of the Belgorod region.

Since Russia launched it invasion on Feb. 24, there have been numerous reports of attacks on Belgorod and other regions bordering Ukraine, with Moscow accusing Kyiv of carrying out the strikes.

Ukraine has not claimed responsibility for previous attacks but has described the incidents as payback and “karma” for Russia’s invasion.

Moscow calls its actions a “special military operation” to disarm Ukraine and protect it from fascists. Ukraine and its allies in the West say the fascist allegation is baseless and the war is an unprovoked act of aggression.