Russia’s Federal Security Service (FSB) said Wednesday that it arrested two Moldovan citizens on suspicion of spying and accused Moldova’s government of trying to undermine its national security.

The FSB said in a statement that the two men are suspected of working illegally for Moldova’s Security and Intelligence Service.

Chisinau did not immediately comment, though it has previously accused Russia of espionage.

According to the FSB, the men arrived in Russia using fake identification and attempted to carry out tasks “directed against the security of the Russian Federation,” though it did not provide further details.