Ukraine's SBU security service said Wednesday it had detained two agents of Russia's intelligence agency accused of passing the location of sensitive military targets to enemy forces.

Kyiv has waged an intense crackdown on those suspected of having collaborated with Moscow since its invasion in February 2022, opening thousands of criminal cases.

"As a result of a special operation, two FSB agents were detained in Kyiv and Odesa," the SBU said in a statement, referring to the Kremlin's FSB security service.

"The criminals tried to identify the locations of Ukrainian troops, and then send the occupiers the relevant coordinates to adjust air attacks," it said.

"At the final stage of the special operation, both criminals were detained red-handed while spying on potential targets for the occupiers," it added.

One of the suspects photographed a thermal power station, ostensibly to help Russia with its bombardment of Ukrainian energy infrastructure, it said.

Both were charged with collaboration and face life in prison.

The United Nations said last year Ukraine had opened more than 6,600 criminal cases "against individuals for collaboration and other conflict-related crimes" since the war began.