Mr Smirnov also added that thousands of people had fled the affected areas and that doctors from Moscow and St Petersburg were en route to provide assistance.
On Wednesday evening, Ukrainian lawmaker Oleksiy Honcharenko said the Ukrainian military had seized control of the Suzhia gas hub, a key gas facility that transports natural gas from Russia to the EU, and despite the war, the flow continues.
Although the BBC has not confirmed this, Mr Honcharenko's comments are the first confirmation that members of the Ukrainian government have entered Russian territory. Kyiv has not previously commented on reports of cross-border attacks.
In a televised address broadcast Wednesday afternoon, Russian General Staff Chief of Staff Valery Gerasimov told Putin that the “advance” into the Kursk region had been halted as Russian forces “continue to destroy the enemy in the areas directly adjacent to the Russian-Ukrainian border.”
Mr Gerasimov also said up to 1,000 Ukrainian troops had entered the area to seize control of the area around the village of Suja, and that Russian forces had already killed 100 people and wounded 215.
However, some popular and generally well-informed pro-war Telegram channels suggested that the situation on the ground was not as stable as the Kremlin had portrayed it to be.
Blogger Yuri Kotenok described the fighting in Suja and nearby Korenevo as “heavy”, while the Rybar channel said the situation in the area around Suja was “continuing to deteriorate” and Ukrainian troops were advancing on the town. The BBC could not confirm these claims.
Kursk officials said thousands of local residents had fled their homes, and Russian National Guard troops had beefed up security at the Kursk nuclear power plant, about 70 kilometers (43 miles) northeast of Sudzha.
Speaking ahead of a UN Security Council meeting in Moscow, President Putin accused Ukrainian forces of “indiscriminately firing” at civilian buildings and residential areas.
