MOSCOW • A Russian state TV channel aired videos on social media of two Americans who went missing earlier this month while fighting alongside the Ukrainian army, stating they had been captured by Russian forces.

US President Joe Biden had said earlier on Friday he did not know the whereabouts of Mr Alexander Drueke and Mr Andy Huynh, US military veterans with whom relatives had lost contact.

The missing Americans - and a third identified as a former US Marines captain - are believed to be part of an unknown number of mostly military veterans who have joined other foreigners to volunteer alongside Ukrainian troops.

On Friday evening, Russian journalist Roman Kosarev - who works for state TV RT channel - posted a video on messaging platform Telegram of Mr Drueke.

"Mum, I just want to let you know that I'm alive and I hope to be back home as soon as I can be," said Mr Drueke, seated facing the camera in what appeared to be an office and dressed in military fatigues.

RT's official Telegram channel also posted an interview with Mr Huynh, in which he said the duo had been "engaged in combat with Russian troops" near Ukraine's flashpoint Kharkiv area.

The pair were also filmed in separate RT videos - directly facing a camera angled from above - saying "I'm against the war", in poor Russian. The circumstances under which they were speaking were not clear, nor who was holding them.

During a White House briefing on Friday, Mr Biden urged US citizens not to go to Ukraine.

The Russian proxy authorities in the so-called Donetsk People's Republic, a Moscow-controlled swathe of eastern Ukraine, have sentenced to death two British men and a Moroccan captured earlier in fighting.

AGENCE FRANCE-PRESSE