"A (prisoner) exchange operation will take place today under the co-ordination of our organisation," the Turkish National Intelligence Agency (MIT) said in a statement.
"Our organisation has undertaken a major mediation role in this exchange operation, which is the most comprehensive of the recent period."
Both the Kremlin and the White House declined to comment when asked about a possible exchange.
Flight tracking site Flightradar24 showed that a special Russian government plane used for a previous prisoner swap involving the United States and Russia had flown from Moscow to the Russian exclave of Kaliningrad, which borders Poland and Lithuania, before heading back to the Russian capital.
A Reuters reporter also saw a Russian government plane in the Turkish capital Ankara.
A number of US citizens are being held in Russian prisons, including jailed Wall Street Journal reporter Evan Gershkovich.
Paul Whelan, a former US marine, and Vladimir Kara-Murza, a Russian-UK dissident, both jailed in Russia, have suddenly disappeared from view, according to their lawyers.
US citizen Paul Whelan was arrested on espionage charges in Russia. (AP PHOTO)
At least seven Russian dissidents were unexpectedly moved from their prisons in recent days.
A lawyer for Alexander Vinnik, a Russian held in the United States, declined on Wednesday to confirm the whereabouts of his client to the state RIA news agency "until the exchange takes place".
RIA also reported that four Russian citizens jailed in the United States had disappeared from a database of prisoners operated by the US Federal Bureau of Prisons.
A lawyer for Russian citizen Alexander Vinnik, held in prison in the United States, did not comment. (AP PHOTO)
It named them as Vinnik, Maxim Marchenko, Vadim Konoshchenok and Vladislav Klyushin.
Dissidents inside Russia whose supporters say they have been told that they have been suddenly moved in recent days include opposition politician Ilya Yashin, human rights activist Oleg Orlov and Daniil Krinari, convicted of secretly co-operating with foreign governments.
Among those Russia has signalled it wants is Vadim Krasikov, a Russian serving life in Germany for murdering an exiled Chechen-Georgian dissident in a Berlin park.
