According to Tass news agency, a shell hit a temporary Russian military camp near the Ukrainian border late Tuesday, and early data revealed it was shot from the Ukrainian side, according to a source.
Tass released the story immediately after a senior local official reported a series of explosions near the Ukrainian border outside the city of Belgorod.
Ammunition appeared to be exploding up in the distance in video released online by two local Belgorod news agencies, but Reuters was not able to corroborate this.
According to Tass, four persons were hurt in the incident, according to an emergency services source.
The blasts occurred in the village of Krasny Oktyabr, around 30 kilometers (19 miles) southwest of Belgorod, according to Belgorod governor Vyacheslav Gladkov. He did not provide an explanation for the explosions and promised to provide an update later.
Belgorod is located 80 kilometers (50 miles) north of Kharkiv, Ukraine, which has been brutally bombed by Russian soldiers in recent weeks.