US journalist Evan Gershkovich and former US marine Paul Whelan are expected to be released by Russia as part of one of the biggest East-West prisoner swaps since the Cold War, according to US media on Thursday.

CNN and other US networks reported the news, with ABC News reporting that the swap involved numerous countries and Russia.

There was no immediate confirmation from US officials. The Kremlin declined to comment on any exchange.

"I still have no comment on this topic," Kremlin spokesman Dmitry Peskov said.

Wall Street Journal reporter Gershkovich, 32, was detained in March 2023 and convicted in July on spying charges in a fast-track trial denounced as a sham by the United States.

Signs of an imminent prisoner swap had picked up momentum on Thursday, amid reports a plane used in a previous exchange deal had landed in the Russian exclave of Kaliningrad.

Hopes had also risen in recent days days after a number of high-profile prisoners in Russia, including Whelan, went missing from prisons where they were serving long terms.

Among those expected to be returned to Russia in exchange is Vadim Krasikov, a Russian citizen imprisoned in Germany for killing a former Chechen rebel commander in a brazen assassination.

The exchange would be a victory for US President Joe Biden, whose vice president, Kamala Harris, faces Republican Donald Trump in the November election.

This would be the first prisoner exchange between Russia and the West since star US basketball player Brittney Griner was swapped in return for convicted Russian arms dealer Viktor Bout in December 2022. (AFP)