Videos that appear to show two American veterans who have been missing in Ukraine since last week surfaced on social media Friday -- the strongest evidence to date that the men have been captured, though so far unconfirmed by the U.S. government.

Alexander Drueke, a 39-year-old Army veteran, and Andy Huynh, a 27-year-old Marine veteran, traveled to Ukraine in April. A source tells Military.com that the pair were captured covering a "tactical withdrawal" near the city of Kharkiv.

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The two videos -- both less than 10 seconds in duration -- each show one of the men sitting in front of an empty wall in a well-lit room, wearing clip-on microphones and looking up at the person recording the video. Both say, "I am against war" -- Drueke in English and broken Russian, Huynh just in Russian. Drueke also identifies himself.

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Dianna Shaw, Drueke's aunt, told Military.com she has seen the videos and that the men "look clean and in relatively good shape, which is a huge relief." Drueke is clothed in an olive T-shirt, while Huynh is wearing a dark green sweater. Neither appears to be injured.

"To the people who have them," Shaw pleaded, "we appeal for Alex's and Andy's humane treatment while our government works to secure their release."

Nothing in the videos indicates when or where they were recorded.

The development comes as the United States continues to provide arms and ammunition to the Ukrainian military. On Wednesday, President Joe Biden announced that he will send an additional $1 billion in weapons and aid to Ukraine. In some cases, those weapons have come with agreements limiting their use in an effort to avoid escalating the conflict. Biden has pledged that American forces will not directly confront Russian troops, but the capture of American veterans fighting in eastern Ukraine, if confirmed, would add a new wrinkle to the tensions between Washington and Moscow.

Unconfirmed reports of the two veterans' capture, including an image of the two men apparently handcuffed in the back of a military vehicle, started circulating on Russian social media Thursday with no clear response from Western governments as to their veracity or whether the veterans are alive or in Russian custody.

A fighter, who said he was in Drueke and Huynh's volunteer unit, said that the two veterans were part of a group attached to Ukrainian forces when, on June 9 during a mission northeast of the Ukrainian city of Kharkiv, the contingent was met by Russian forces. The fighter asked to remain anonymous, but provided Military.com with proof of his identity and proof of his association with the two missing veterans.

Shaw said that the State Department "has" the videos and is "working quickly to verify them." She previously said that they were also "aware of photographic evidence of capture circulating on Russian media" and working to verify its authenticity. Military.com could not verify any further details about the images or videos.

Military.com reached out to the State Department for a comment on the videos and was directed back to a briefing conducted by spokesman Ned Price on Thursday.

At that briefing, Price said that the State Department hasn't "seen anything" regarding the two veterans' potential capture by the Russians.

Russian state media has already begun discussing the fate of the two men. In a clip posted by Russian media observer Julia Davis on Thursday, the host began a segment by saying that "it seems two Americans have been captured" before adding: "I can only imagine what will happen" and citing The Telegraph's original reporting on the men's capture.

"Now, as I understand, there will be a trial," the host said. "Based on the precedent, there will be a death sentence," he added -- likely a reference to two captured British volunteers in Ukraine who were sentenced to death by a high court in the Russian-backed Donetsk People's Republic. Both British and U.N. officials sharply condemned those sentences.

A member of the Russian Duma -- the country's legislative body -- and a guest on the segment agreed before adding, "There are no other options."

A third American, Grady Kurpasi, a decorated Marine veteran, is also missing after traveling to Ukraine to fight, his wife confirmed to Military.com. Kurpasi deployed to Iraq three times, according to details of his service provided by the Marine Corps, and earned a Combat Action Ribbon and Purple Heart, as well as several personal commendation awards.

Military records for Drueke show that he served as a "chemical operations specialist" for 12 years with the Army Reserve and deployed to Iraq and Kuwait, leaving the service as a staff sergeant. Meanwhile, Huyhn was an "engineer equipment operator" who left the Marines after four years at the rank of corporal and never deployed.

The State Department has called on Russia to follow the rules of armed conflict and the Geneva Conventions, which protect uniformed fighters against being held criminally liable for fighting in a recognized war. Russian officials have publicly stated that they view all volunteer fighters as mercenaries.

-- Konstantin Toropin can be reached at konstantin.toropin@military.com. Follow him on Twitter @ktoropin.

-- Drew F. Lawrence can be reached at drew.lawrence@military.com. Follow him on Twitter @df_lawrence.

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