Ukraine says it has pressed its surprise offensive in Russian territory and bombarded the neighbouring border region of Belgorod.

“As of today, our troops have advanced in some areas by one to three kilometres,” Ukrainian President Volodymyr Zelenskyy.

His military chief, Oleksandr Syrskii, said their forces have taken “control [of] over 40 square kilometres [15sq miles] of territory” and that 74 settlements are under Ukrainian control.

After a week of the Ukrainian advance, Syrskii said on Monday that his troops controlled about 1,000sq km (386sq miles) of Russian territory.

“The situation in our Belgorod region remains extremely difficult and tense due to shellings from the Ukrainian Armed Forces. Houses are destroyed, civilians died and were injured,” Belgorod governor Vyacheslav Gladkov said on Telegram.

“A state of emergency will be introduced on the regional level, followed by a request to the governmental commission to declare a federal state of emergency.”

Gladkov said the area had been hit by Ukrainian drones.

“Two settlements in Belgorod region were attacked by the Ukrainian Armed Forces’ drones. There were no casualties,” he said. “In Shebekino, as a result of several drone attacks on an apartment building, one apartment caught fire and slabs collapsed. The gas supply line was also damaged.”