Paul Whelan stands inside a defendants' cage during a hearing at a court in Moscow on August 23, 2019.
Washington CNN  — 

Paul Whelan, an American imprisoned in Russia, said he was assaulted by a fellow prisoner at his remote labor camp in Mordovia.

In an audio statement shared with CNN, Whelan said he “was assaulted by a Turkish prisoner, 50 years old, who has recently arrived at the prison and has anti-American leanings.”

Whelan said he was working in a factory at the camp Tuesday when the other prisoner struck him in the face “with his closed fist” and then tried to strike him “with his open hand.”

“I stood up to block the second hit, being concerned that he had sharp shears in his hand that could be used as a weapon. Other prisoners stopped him from further assault while I left the area, looking for guards,” Whelan said. “There are no guards on the factory floor and it was quite difficult for me to find prison staff to assist.”

Whelan said he had seen the prison doctor and reported the incident to the deputy warden, and “the prison is taking the incident seriously.”

“I am asking to speak to the prosecutor in order to press charges for the assault,” he said. Whelan’s family said he spoke with officials from Mordovia later Tuesday.

A State Department spokesperson told CNN that they “are concerned about reports that Paul Whelan was assaulted by another prisoner in IK-17 on November 28.”

“The U.S. Embassy in Moscow has been in contact with Paul via phone and we understand he is receiving medical treatment following this incident,” the spokesperson said.

“We call on Russia to ensure Paul Whelan and all U.S. citizen detainees are safe,” they said. “We urge the Russian government to ensure fair treatment and appropriate medical care for all U.S. citizens detained in Russia.”

“Russia should immediately release Paul Whelan,” the spokesperson said.

Whelan has been designated as wrongfully detained by the US State Department. He has been imprisoned in Russia for almost five years.

Whelan’s reported assault underscores concerns from his family and himself that the longer he remains imprisoned, the more he is at risk.

He told CNN in October that he pressed Secretary of State Antony Blinken in a phone call in August to ensure that he is not left behind in Russia again, telling the top US diplomat “point blank that leaving me here the first time painted a target on my back and leaving me here the second time basically signed a death warrant.”

Whelan said he told Blinken that “unless they got me back, it could be quite challenging in the future, especially with my age and the sort of work we have to do from a health and safety point of view.”

Whelan was not included in prisoner swaps that freed fellow wrongfully detained Americans Trevor Reed and Brittney Griner last year. US officials have said that the Russians refused to include him in those swaps for Konstantin Yaroshenko and Viktor Bout, respectively.

This story has been updated with additional reporting.