Russian forces are obtaining Starlink satellite terminals illicitly from third countries and increasing their use on the front line, the Ukrainian military spy agency's spokesperson told Reuters on Monday, without explaining how he knew.

Andriy Yusov, the military official, said work was underway to prevent Russian forces using the high-speed satellite internet terminals produced by Elon Musk's SpaceX to coordinate attacks in occupied parts of Ukraine.

"Contraband from third countries," Yusov said, when asked how Russian forces were obtaining the devices.

"Useage has increased on the front line," he said.

Ukraine, which uses Starlink for military communications in its war with Russia, said on Sunday that Russian troops were using Starlink in occupied areas as the full-scale war with Russia nears the two-year mark.

Asked if Ukraine was trying to stop Russia's use of the terminals, Yusov said: "Yes, work is being conducted."

The Kremlin said Monday that the terminals were neither certified for use in, nor officially supplied to, Russia, and therefore could not be used.

Starlink says it does not do business of any kind with Russia's government or military.

It said on Feb. 8 that its terminals were not active in Russia and that SpaceX had never sold or marketed the service in Russia, nor shipped equipment to locations in Russia.

Starlink terminals, which provide a high speed internet connection, were rushed in to help Ukraine after Russia's February 2022 invasion and have been vital to Kyiv's battlefield communications.