The Kremlin declined to comment on Thursday when asked about reports that Russia and the West could be gearing up for their biggest prisoner swap since the Cold War.Several prisoners in Russia and Western countries have reportedly been moved from their cells in recent days, fuelling speculation of an imminent exchange."I still have no comment on this subject," Kremlin spokesman Dmitry Peskov told reporters on Thursday.Among those slated to be part of a potential deal is Wall Street Journal reporter Evan Gershkovich, who was sentenced to 16 years in jail last month on spying charges slammed as false by the White House.Several others held in Russian prisons, including opposition figures Vladimir Kara-Murza and Ilya Yashin, have also reportedly been moved, possibly in advance of a deal.Prison transfers are notoriously murky in Russia, where families are not warned beforehand and prisoners often lose contact with their lawyers and the outside world for weeks.Swaps can happen only after a conviction, and the disappearance of several high-profile political prisoners at once is extremely rare.