(CNN) An American veteran and father of five died on Tuesday after sustaining injuries fighting alongside Ukrainian forces in the east of the country, his sister told CNN.
Dane Partridge, 34, from Rexburg, Idaho, had been fighting in Ukraine since the end of April, his sister Jenny Corry said.
Partridge and the other men he was with were clearing trenches when they were ambushed by two Russian vehicles, Corry said. The men were caught in a firefight. Partridge received shrapnel in his brain and suffered from a broken neck and injured arm, Corry said.
Partridge was taken to a hospital in Zaporizhzhia on October 3. He laid in a coma for eight days and passed away on Tuesday while he was still on life support, Corry said.
Earlier on Thursday, a State Department spokesperson confirmed that a US citizen recently died in the Donbas region of Ukraine but they did not confirm their identity.
Partridge was a volunteer fighting alongside Ukrainian forces, Corry said.
"He had a spiritual conviction to just go. He did not have a plan aside from putting on his backpack and showing up in Poland and figuring it out from there," Corry said.
Once he arrived in Ukraine, he joined the international legion of foreign fighters, a group of volunteers from countries around the world fighting alongside Ukrainians, Corry said. Partridge was also involved with an organization called LEGS, Logistical Emergencies Getting Solved, helping to organize rescues of injured civilians in Ukraine, Corry said.
Corry said she was frequently in touch with Partridge in the months he was fighting in Ukraine.
"He said it was something that he'd never encountered before," Corry said of Partridge's descriptions of his time in Ukraine. "It was more than what he had personally experienced in Baghdad."
Partridge's sister said he is a veteran and served in the US Army from 2006-2012. He deployed to Baghdad for Operation Iraqi Freedom for 15 months from 2007 to 2009. The US Army confirmed Partridge did serve during that time with one deployment to Iraq, according to US Army spokesperson Matt Leonard. He held the rank of private first class at the end of his service, Leonard said.
Corry described Partridge's feeling that he "just needed to serve" in Ukraine.
"He needed to be always working in a job that would allow him to serve his fellow men, and that's how he lived, and that's how he died," Corry said. "He thought he was fighting for a noble cause."
Partridge's body will be returned to the US, Corry said. It is currently in transit back from Ukraine, she added. The family plans to bury Partridge in a Veterans Affairs cemetery in Idaho, she said.
Four other Americans are known to have been killed in the country fighting alongside Ukrainian forces during the ongoing conflict with Russia. Willy Joseph Cancel, 22, was killed on April 25, his mother Rebecca Cabrera told CNN.
US citizen Stephen Zabielski died in mid-May, the State Department confirmed, and two other Americans died in the Donbas region in July, the State Department said. One of them was Luke Lucyszyn, his mother Kathy Lucyszyn told CNN.
This story has been updated with additional reporting.