A residential building and a barn in the village of Poroz were "completely burned down", Vyacheslav Gladkov said. Another building was severely damaged.

"As a result of the release of two explosive devices, a private residential building caught fire. Tragically, two civilians died -- a woman who was recovering from a fractured femur, and a man who was caring for her," Gladkov wrote on Telegram.

"The son of the deceased managed to run out of the burning house at the last moment."

Earlier, he reported another Ukrainian drone strike on the village of Istobnoye, with no casualties.

The governors of Kursk, Kaluga and Bryansk, all in western Russia, reported strikes on their regions as well.

The defence ministry said it intercepted 50 Ukrainian drones overnight, including 26 over the Belgorod region and one over territory surrounding Moscow.

Ukraine has stepped up its attacks on Russia in recent weeks, targeting energy sites in particular.

With his country reliant on Western, primarily US, military support to counter the Russian offensive, Ukrainian President Volodymyr Zelensky has been frantically urging allies to accelerate the weapons supply to his struggling, outgunned forces.

In the United States, lawmakers will vote on Saturday over whether to unlock a long-delayed $61-billion military aid package that has been stymied by political infighting.

Zelensky has called it a "vitally important decision".