Russia and the United States have agreed to swap prisoners, according to U.S. media on Thursday.

The swap will allow Wall Street Journal (WSJ) reporter Evan Gershkovich and former U.S. Marine Paul Whelan, who were jailed in Russia on espionage charges they and the U.S. deny, to be in the care of U.S. officials, CNN and other U.S. networks reported.

CNN, citing a source, said the "large-scale prisoner swap" is underway, with CBS News saying the exchange has not occurred yet but is expected later on Thursday.

There has been no official response from Russia.