MOSCOW — Two American volunteers fighting for Ukraine were taken into detention by Russian-backed separatists in Donetsk after being captured last week, according to Russian state media.

US citizens Alexander John-Robert Drueke, 39, from Tuscaloosa, Alabama, and Andy Tai Ngoc Huynh, 27, from Hartselle, Alabama, were interviewed by Russia's RT channel at a detention center in the so-called Donetsk People's Republic (DPR) on Friday, according to a report published on RT.

The two Americans went missing on June 9 during a battle north of Kharkiv and it was feared that they may have been captured by Russian forces, according to their families and a fellow fighter.

On Friday, short video clips surfaced on pro-Russian channels and social media appearing to show the men detained at an unknown location. At the time it was not clear who was holding them.

A State Department spokesperson told CNN on Friday they "have seen the photos and videos of these two US citizens reportedly captured by Russia's military forces in Ukraine" and were "closely monitoring the situation."

"We are in contact with Ukrainian authorities, the International Committee of the Red Cross, and with the families themselves," they continued. "Due to privacy considerations, we have no further comment on these cases."

Separately, a more than 50-minute edited video was published on Saturday of Drueke and Huynh being interviewed by HelmCast, a pro-Russian Serbian nationalist YouTube channel.

In the interview, a man can be heard behind the camera revealing the location of their interview when he says, "here in Donetsk" during a question to Drueke.

Drueke is also asked in the interview if he has any objections to how he has been treated since his capture and he reveals he has been beaten.

CNN is choosing not to broadcast the videos of US detainees because they show the men speaking under duress.

The location of Drueke and Huynh's detention is a potentially concerning development. Russia has a moratorium on the death penalty, whereas Donetsk uses firing squads to execute condemned prisoners, according to Russian state media RIA Novosti.

On June 9, a court in DPR sentenced foreign fighters, two British citizens and a Moroccan national, to death after accusing them of being "mercenaries" for Ukraine. The internationally unrecognized court in DPR said the men had a month to appeal their verdicts.

Hopes that a prisoner swap between Ukraine and the pro-Russian separatists could free any foreign fighters detained in Donetsk appeared to have been dashed after Denis Pushilin, the self-proclaimed head of DPR, said such exchanges were out of the question.

"The exchange of the British men sentenced to death in the DPR is not under discussion, there are no grounds for pardoning them," Pushilin told independent Russian investigative newspaper Novaya Gazeta on Thursday.

The Donetsk People's Republic did not immediately respond to a request for comment on the detention of Drueke and Huynh.

Speaking exclusively to CNN's Sam Kiley, a former US serviceman fighting with Ukrainian forces recounted the battle he witnessed on June 9, when Huynh and Drueke were purportedly captured.

The man, who asked to be identified with the code name "Pip," said his team was sent out on a mission east of Kharkiv where a full-scale Russian armored assault was underway.

Huynh and Drueke fired an RPG at a BMP -- an infantry fighting vehicle -- that was coming through the woods and destroyed it, according to Pip. But the team had to quickly withdraw as more than 100 Russian infantry began advancing and the American fighters found themselves in a village they previously thought was in Ukrainian hands.

When asked about what happened to Huynh and Drueke, Pip said that "we suspect they were knocked out by either the T-72 tank shooting at them or by the blast of the mine. This is only speculation, we don't know what really happened to them."

Separately, a man who was acting as the team's sergeant and who wished to remain anonymous for security reasons, previously told CNN it "was absolute chaos."

"There was about a hundred plus infantry advancing on our positions. We had a T-72 firing on people from 30, 40 meters away," he said.

A photo of the two men emerged on Thursday with their hands tied behind them and in the back of a Russian truck. The undated photo was posted on Telegram on Thursday by a Russian blogger. CNN could not independently verify when the photo was taken.

A third American, whom the State Department has said is missing in action in Ukraine, was identified as US Marine veteran Grady Kurpasi, his wife confirmed to CNN on Thursday.

The last time Heeson Kim and other close friends heard from Kurpasi was between April 23 and 24, George Heath, a family friend of Kurpasi's told CNN. Kurpasi served in the US Marine Corps for 20 years, retiring in November 2021. He chose to volunteer alongside Ukrainians in Ukraine but initially did not envision himself fighting on the frontlines of the war, Heath said.

On Friday, US President Joe Biden said he has been briefed on the three Americans missing in Ukraine. In remarks to reporters, Biden said repeatedly Americans should not travel to Ukraine at this time.

"We don't know where they are, but I want to reiterate: Americans should not be going to Ukraine now," Biden said in response to a question from CNN's MJ Lee at the White House. — CNN