Russian forces prevented a Ukrainian sabotage and reconnaissance team from piercing the border in the western Bryansk region, about 240 kilometers from the site of Ukraine's incursion into the neighboring Kursk region, a Russian official said.

Russia said on Wednesday that its forces had advanced in eastern Ukraine and had begun to push back Ukrainian forces in the Kursk region, though a senior commander cautioned that Ukrainian forces were regrouping for another possible attack.

Bryansk Governor Alexander Bogomaz said that Federal Security Service border guards and Russian military units repelled an attack by a Ukrainian sabotage and reconnaissance team on Wednesday.

He said the attempted incursion took place in the Klimovo district which borders Ukraine's Chernihiv region. The Bryansk region lies northwest of the Kursk region where a Ukrainian incursion has been underway since early August.

Ukraine smashed through the Russian border in the Kursk region on August 6 in an attempt to force Moscow to divert troops from the rest of the front, though Russian forces have continued to advance in eastern Ukraine in recent days.

Russia's defense ministry said it had shot down 28 drones over Russian territory, including 13 in the Volgograd region, seven in Rostov, four in Belgorod, two in Voronezh and one each in Bryansk and Kursk regions.

A fire broke out at a military facility in Russia's southern Volgograd region after a Ukrainian drone crashed into it on Thursday, regional governor Andrei Bocharov said on the Telegram messaging app.

Bocharov said there were no casualties and did not specify what facility had been attacked, but said the attack focused on the area of the Marinovka village, where a military airbase is located.

Aviation watchdog Rosaviatsia said temporary restrictions were imposed on Thursday on the Volgograd airport, which was not accepting or sending aircraft.