Marine Vet Killed Fighting Alongside Ukrainian Forces

A Russian serviceman accompanies journalists during their visit to the Luhansk thermal power plant in the town of Shchastia, Luhansk region. (Alexey Maishev/AP)

A Marine veteran was believed to be the first American combatant killed during the Russia-Ukraine war.

Willy Joseph Cancel, a 22-year-old New York native, was killed while fighting alongside Ukrainian forces, his family members told CNN.

Cancel's mother, Rebecca Cabrera, told CNN that her son left his full-time job as a corrections officer in Tennessee to work with a private military contracting company in Ukraine. She added that Cancel leaves behind a 7-month-old baby and a wife.

"He wanted to go over because he believed in what Ukraine was fighting for, and he wanted to be a part of it to contain it there so it didn't come here, and that maybe our American soldiers wouldn't have to be involved in it," Cabrera told CNN.

Cabrera was told by those who informed her of her son's death that his body had not been found, CNN reported.

"They haven't found his body," Cabrera told the network. "They are trying, the men that were with him, but it was either grab his body or get killed, but we would love for him to come back to us."

A State Department official told CNN they are "aware of these reports [concerning Cancel] and are closely monitoring the situation."

"Due to privacy considerations, we have no further comment," the official told CNN. "We once again reiterate U.S. citizens should not travel to Ukraine due to the active armed conflict and the singling out of US citizens in Ukraine by Russian government security officials, and that U.S. citizens in Ukraine should depart immediately if it is safe to do so, using any commercial or other privately available ground transportation options."

Cancel's brother-in-law, Devin Tietze Jr., told CNN that Cancel originally was from Orange County, New York, and had been living in Tennessee before he left for Ukraine.

"He believed wholeheartedly this shouldn't have happened, and he wanted to go help the people in Ukraine," Tietze told CNN in a phone interview.

Cancel was not the first American killed in Ukraine since Russian President Vladimir Putin began his country's unprovoked attack on Ukraine Feb. 24.

Jimmy Hill, a 67-year-old Idaho man, was gunned down in the streets of Ukraine while buying bread after refusing to leave the warzone because he was looking after his sick partner, the Daily Mail reported.

Brent Renaud, a 50-year-old Little Rock, Arkansas native and an acclaimed filmmaker, died after Russian forces opened fire on his vehicle in Ukraine..