Officials and family members said Wednesday that two Americans who volunteered to help Ukraine have gone missing and are believed to have been taken prisoner by Russia.

Alexander Drueke, 39, and Andy Tai Ngoc Huynh, 27, are both U.S. military veterans who lived in Alabama before traveling to Ukraine to help with the war effort. Relatives have contacted Senate and House offices in search of information on the men's whereabouts.

On June 8, both men informed their families that they would be going offline for a few days but did not provide any details for fear of their connections being intercepted.

Americans would become Russian prisoners of war for the first time since the February invasion, joining other foreign nationals captured while fighting for the Ukrainian war effort.

According to one former private military contractor, the professional term for a soldier-for-hire, who knows the large network of U.S. military veterans who have gone to Ukraine, many are unaware of the realities of this particular conflict.

"If it's real," White House spokesman John Kirby said of the two Americans' disappearance, "we'll do all we can to get them safely back home." He claimed that the US discouraged Americans from visiting Ukraine, which has been fighting to invade Russian forces for nearly four months.

Drueke served two tours in Iraq, the most recent as a lead gunner in Baghdad in 2008-09, according to his mother. Huynh is a former U.S. Marine who left the service in 2018, according to his fiancee.

They claimed the men had never met before meeting in Ukraine, but felt compelled to back the government after seeing images of civilian casualties as Russia withdrew from towns outside Kyiv in late March.

Joe Biden announced another $1 billion in military aid to Ukraine earlier Wednesday but has stated that US forces will not engage Russia, a fellow nuclear power, directly.

It has been reported last week that two British fighters captured by Putin's forces in Ukraine and paraded on Russian state television could face the death penalty for their crimes, according to the prosecutor of the so-called Donetsk People's Republic.

The Kremlin has warned that if the United Kingdom appeals the death sentence handed down to two British fighters captured in Ukraine, Russia "will be ready to listen."

Aiden Aslin and Sean Pinner, as well as Moroccan national Brahim Saadoun, were informed last week that they would be executed by firing squad for allegedly fighting as mercenaries for Ukraine.

They were exhausted from what the United Kingdom has called 'sham' proceedings in the self-proclaimed Donetsk People's Republic in eastern Ukraine, which is ruled by Russia-backed separatists.