The United States is releasing an unidentified Russian prisoner as part of the deal to secure Marc Fogel's freedom, the Kremlin announced Wednesday. 

Fogel, an American teacher who had been detained in Russia since 2021, was freed on Tuesday. A plane carrying him landed in the U.S. late last night. 

Kremlin spokesman Dmitry Peskov said the Russian prisoner’s name would be revealed when he returns home. 

"Recently, work has been intensified through the relevant agencies, there have been contacts," Peskov said in a conference call with reporters, according to the Associated Press. "And these contacts have led to the release of Fogel, as well as one of the citizens of the Russian Federation, who is currently being held in custody in the United States. This citizen of the Russian Federation will also be returned to Russia in the coming days." 

FREED AMERICAN HOSTAGE MARC FOGEL LANDS IN US AFTER YEARS IN RUSSIAN CAPTIVITY 

The State Department did not immediately respond Wednesday morning to a request for comment from Fox News Digital. 

Fogel, a history teacher from Pennsylvania, was serving a 14-year prison sentence after his arrest in August 2021 at a Russian airport for being in possession of drugs, which his family and supporters said were medically prescribed marijuana. 

Anne Fogel, his sister, told "Fox & Friends" on Wednesday that she is "so happy to have this massive boulder" lifted off her shoulders with her brother’s release. 

"I am so incredibly grateful to the president," she added. "Just amazing." 

Fogel said her brother's situation has "taken a toll" on her family but they "can’t even believe that he is safe and at home and can get medical attention." 

AMERICAN MARC FOGEL RELEASED FROM RUSSIAN CUSTODY 

After his arrival in the U.S., Fogel met with President Donald Trump at the White House and called him a hero for securing his release. 

"I want you to know that I am not a hero in this at all. And President Trump is a hero," Fogel said after meeting Trump. 

"These men that came from the diplomatic service are heroes," Fogel continued. "The senators and representatives that passed legislation in my honor – they got me home – they are heroes." 

When asked by reporters on Tuesday whether the U.S. had given up anything in return for Fogel, Trump replied "not much" without offering additional details. 

Fox News’ Landon Mion and the Associated Press contributed to this report.