A former US Marine who was hired to fight alongside Ukrainian soldiers against Russian invaders was killed this week.

Willy Joseph Cancel, 22, was being paid by a private military contracting company to fight in Ukraine when he died on Monday, family members told CNN.

“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,” Cancel’s mother, Rebecca Cabrera told the network.

Cancel flew to Poland on March 12 and arrived in Ukraine the next day to fight alongside men from “all different countries,” Cabrera reportedly said.

The circumstances of Cancel’s death were not immediately clear, and officials that notified his family of the death had not recovered him, his mom explained.

“They haven’t found his body,” Cabrera reportedly said. “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.”

Cancel, an Orange County, New York native, had reportedly signed up for the contract work earlier this year to supplement his full-time job as a Tennessee corrections officer.

Cancel was being paid by a private military contracting company to fight in Ukraine.AP/Emilio Morenatti

He left behind a 7-month-old baby and a wife, according to the article.

The US State Department reportedly said it was “closely monitoring the situation,” as it reiterated its recommendation that US citizens should avoid traveling to Ukraine “due to the active armed conflict and the singling out of US citizens in Ukraine by Russian government security officials.”

Cancel’s brother-in-law Devin Tietze Jr. told CNN the military man was the “type to fight for what’s right regardless of the outcome,” and “always put everybody ahead of himself.”

James Whitney Hill, of Idaho, is seen in a Facebook photo.James Whitney Hill, an American citizen who had been living in Ukraine and working as a teacher for 25 years, was killed last month.Facebook/Jimmy HIll

“He was just a really thoughtful person,” Cabrera reportedly added. “He always kept everybody laughing and calm. He was the man that stood up when everybody else stood back.”

Cancel was not the first American to die in the conflict. James Whitney Hill, 67, was killed in an attack on a Chernihiv bread line last month. He had been living in Ukraine and working as a teacher for 25 years, family members told The Post.

Former New York Times contributor Brent Renaud, 51, was fatally shot in the neck by Russian troops in Irpin days before Hill’s death. American photojournalist Juan Arredondo was also injured in that attack.

More than 20,000 volunteers and veterans from 52 nations had signed up to join the Ukrainian military’s International Legion for foreign fighters that wanted to defend the country from Russia’s unprovoked attack, CNN reported.

On Thursday, a United Kingdom resident had been killed in Ukraine and another was missing, British officials said.

With Post wires