(NewsNation) — At least three Americans with military experience are believed to be captured in Ukraine.

Alabama residents Alex Drueke and Andy Huynh are believed to be in Russian custody and have been spotted in video released by their captors.

Grady Kurpasi Jr. has not been heard from since late April. His father thinks Kurapsi Jr., a U.S. Marine veteran, is a prisoner of war. He tells NewsNation his son’s cellphone was tracked to a mall in Kherson that is reportedly being used as a Russian prison.

An American in Ukraine, going by Isaac for his safety, says he fought alongside Kurpasi Jr.

Isaac says he lost contact with Kurpasi Jr. in late April. The former major in the U.S. Marines remembers last speaking to him about the mission and how to be more effective in the fight against the Russians.

Isaac spoke to “NewsNation Prime” on Tuesay about what it’s like in Ukraine right now and the challenges that forces are up against.

“The level of destruction is beyond belief,” Isaac said. “When you take into account the artillery, presence of tanks, you know, it’s nothing like I ever experienced in the 14 years in the Marine Corps with service in both Iraq and Afghanistan.”

Isaac says most of the villages where fighting is taking place are devoid of human life. When asked if it’s a fair fight, Isaac replied, “Ukraine is definitely outgunned and outmanned. However, it is doing absolutely everything it can. They’re making heroic efforts.”

He believes the outcome of the war will largely depend on the level of support countries of the West are able to send to Ukraine.

“I expect that the government is going to take its official position,” Isaac said. “However, people like myself and the other people who were there as volunteers were guided by our conscience. We’re well aware of the risks.”

The State Department is warning Americans not to travel to Ukraine.