At least five Americans, including a military veteran from Idaho, have died while fighting against the Russians.
A Russian tank attack on his unit left him with critical injuries to his neck and brain stem and he was on life support.
During the last week of his life, he was in a coma, and his family had to say goodbye through a video call.
Jenny Corry told the Washington Post that her brother, who served as an Army infantryman during a tour of Iraq between 2007 and 2009, felt like he needed to fight.
Corry said in a post that members of his family believe they will be able to bring his body back to Idaho.
The State Department confirmed to Forbes that an American died recently in Ukraine's eastern Donbas region but did not confirm the individual's identity or any further information out of respect for the privacy of their family.
The number of U.S. citizens who have volunteered to fight in the Ukrainian forces is unknown. The Ukrainian Embassy in Washington, D.C. told the Washington Post in March that 4,000 people had expressed interest in joining the International Legion of Territorial Defense of Ukraine. According to reports, at least four Americans have been killed fighting in the country this year. Ukrainian officials say that an American documentary filmmaker died after being shot in the neck by Russians.
Americans are not allowed to go to Ukraine to fight in the war.
The Washington Post reported on the death of an American veteran.