Moscow said on Tuesday its army had beaten back Ukrainian forces trying to claim territory in two Russian border regions, deploying warplanes, missiles and artillery to fend off the assaults.

The announcement came after several groups of Russian volunteers fighting for Ukraine said they had crossed the border in the region of Kursk in western Russia.

The defense ministry said that Russian forces “thwarted an attempt by the Kyiv regime to make a breakthrough into the border territory of the Russian Federation in the Belgorod and Kursk regions.”

It said the first attempt began at 3:00 a.m. local time (00:00 GMT) in the Belgorod region but that the Russian military and the Federal Security Service beat back the attacks.

It claimed without providing evidence to have destroyed dozens of Ukrainian servicemen as well as several armored vehicles.

A second attempt started approximately three hours later in the neighboring region of Kursk, also bordering Ukraine, the defense ministry said.

“Having suffered significant losses, the enemy was driven back,” the defense ministry said in its statement.