The family of a former U.S. soldier captured in Ukraine said Tuesday he has contacted the U.S. State Department twice since the weekend to read statements that identified his captors as forces from the Donetsk People's Republic, a Russian-backed region in Ukraine.
Alex Drueke, 40, left his home from outside Tuscaloosa, Alabama in mid-April, intending to join Ukrainian forces as a volunteer. Upon arrival, he helped train soldiers on equipment they received from other nations.
Drueke last contacted his family on June 13, they said. On June 15, photos of Drueke and Andy Huynh started appearing online via Ukrainian and Russian social media that showed the men in captivity.
MORE: US to purchase advanced missile system for Ukraine's defenseAccording to Drueke's aunt, Dianna Shaw, Drueke first called the State Department Saturday from a Russian phone number. He read a statement that said the DPR wanted to negotiate the release of Drueke and Huynh. He added that he was being treated well and had shelter and water.
During a second phone call on Tuesday, Drueke read a second statement from his captors regarding negotiations without specifying terms, she said. He said he was spending most of his time in solitary confinement and had not seen Huynh in several days, according to Shaw.
"We have been in contact with the Ukrainian and Russian authorities regarding U.S. citizens who may have been captured by Russia's proxies while fighting in Ukraine," the State Department said in a statement to ABC News. "We are seeking to learn as much as we can and are providing every form of support possible, including for the families, with whom we are in contact. Due to privacy considerations, we have no further comment at this time."
The Kremlin has not confirmed where both men are being held.
MORE: 2nd American confirmed dead in UkraineShaw said the phone calls are evidence that "Russia knows the world is watching" and suggested the Russian government is playing a role in protecting the men.
"Russia has the influence over their surrogates to see that Alex and Andy are given humane treatment as POWs and eventually released unharmed," she said.
On Friday, Ukrainian President Volodymyr Zelenskyy called both men "heroes" and said he would fight for their release.
MORE: US nuclear scientist reportedly rescued from Russia-occupied Ukraine"We'll fight for them and get them back, and of course they will come back to their families," he said. "To me, it is a great honor that in the world there are some soldiers that are not afraid, and they came to support us and our sovereignty and independence."
In a statement, Bunny Drueke, the veteran's mother, said it was "very encouraging to hear the Ukrainian government is committed to securing Alex's and Andy's release."
Drueke served in the U.S. Army for 12 years, including two tours in Iraq.