At least, three people were killed and four injured in a series of “strong explosions” that rocked the city of Belgorod early on Sunday, according to the governor of the region, which borders Ukraine.

“We are currently trying to establish the circumstances of the incident. The anti-aircraft defences were in operation,” Belgorod Governor, Vyacheslav Gladkov, said on Telegram.

Eleven residential buildings and 39 houses were damaged in the explosions which occurred in the early hours, the governor had said.

He, however, stopped short of accusing Ukrainian forces of being behind the strikes.

Gladkov said he visited the site very soon after the explosions, which hit five streets to the North of the city centre.