Two U.S. military veterans have gone missing in Ukraine and are feared to have been captured by Russian forces, family members of the missing Americans said Wednesday. Alexander J. Drueke, 39, and Andy Tai Huynh, 27, both from Alabama, have been missing in recent days near Kharkov, a Ukrainian town not far from the Russian border, according to their families. Drueke had served in the U.S. Army and Huynh is a Marine Corps veteran, they said. In telephone interviews, both families shared similar accounts to which the men had contacted them on June 8 to tell them they would be inaccessible during a multi-day mission. There has been no update since, they said. Drueke’s mother, Lois, said she received a phone call Monday from another U.S. citizen indicating she was in Ukraine with her son. The caller, who did not identify him, told her that the intercepted communications suggested that Russian forces had arrested two Americans, he said. The Russian embassy in Washington did not immediately respond to a request for comment. Volunteers of the war in Ukraine are returning home, calculating a difficult struggle Alexander Drueke had told his family that he was teaching Ukrainian troops how to use American-made weapons, his mother said. “Alex felt strongly that he had been trained in ways that could help Ukrainians be strong and push Putin away,” she said, referring to Russian President Vladimir Putin. “He went there not to fight, but to train.” Joey Black, who identified herself as Huynh’s fiancée, said she had volunteered to fight alongside Ukrainian forces. She also received a phone call on Monday from someone who looked American and told her that Huynh was missing. “The response we received from our government was very helpful,” Black said. “It simply came to our notice then. “We received the call on Monday morning, and it just went up so high, so fast.” The news of the disappearance of the Americans was first reported on Wednesday by the Telegraph of London. The State Department said the Biden administration, which has discouraged Americans from participating in the war, “knew of unconfirmed reports of two American citizens being detained in Ukraine,” but declined to comment further. “We are closely monitoring the situation and are in contact with the Ukrainian authorities,” the statement said. “We also reiterate that US citizens should not travel to Ukraine because of the active armed conflict and the expulsion of American citizens to Ukraine by a Russian government official.” Speaking to the media Wednesday afternoon, White House spokesman John Kirby said he had no information to share about the missing Americans or whether the U.S. government believes they have been taken prisoner. The American who was killed in Ukraine was a volunteer, say comrades-in-arms The situation creates another challenging scenario for the United States in its diplomacy with Russia. The Kremlin has held other Americans for months or years, including WNBA star Brittney Griner and Marine Corps veteran Paul Whelan. Another US detainee from Russia, Marine Corps veteran Trevor Reed, was released on bail in April. It is not clear how many Americans have participated in the war. Shortly after the conflict began in late February, Ukrainian officials said about 4,000 had expressed interest in doing so. At least one American citizen, Marine Corps veteran Willy Joseph Cancel, 22, was killed in the battle. Drueke served two tours in Iraq with the U.S. military, leaving around 2010 as a sergeant, his mother said. He had struggled with post-traumatic stress disorder since leaving the army, but seemed to find purpose in sending troops to Ukraine, he added. Huynh served in the Marine Corps for a number of years, including the Japanese island of Okinawa, his fiancée said. The Washington Post could not immediately verify the military history of both. Lois Drueke said she last spoke to her son on the phone on June 5 and then received a message three days later on the encrypted Signal communications platform. His message was that he would be “darkened” and inaccessible for a few days and that he would be in touch again after completing a mission. Alice Crites and Missy Ryan contributed to this report.