(NewsNation) — A U.S. Marine who enlisted in the Ukrainian military soon after the Russian war broke out said what he’s seen has been shocking.

“It is a heavy, modern sustained invasion and the combat is nothing like anything I’ve ever seen before in my time in the Marine Corps. It’s worse than anything I’ve experienced before,” the Marine said on “NewsNation Prime” on Thursday night. To protect his identity, he has asked to be referred to as Jorge David.

David served in Afghanistan in 2010, and said in another interview he considered that a rough deployment until this war.

He says basic supplies such as sleeping bags and winter clothes are running low in his unit. But there is an abundance of determination and will. Their ability to hold the Russians off this long has only strengthened their resolve.

“It would appear the Russians are tactically unaware, inept,” David said.

The decision to head to Europe to fight became inevitable for David. He was having trouble concentrating at his day job in Mexico, where he lived before the war.

“I couldn’t enjoy myself, the small things of daily life,” he said.

Three days into the conflict, he determined the only way to overcome that feeling was to do what his gut was telling him to do.

He made his way to Ukraine among a cavalry of other foreign fighters who had that same nagging feeling: They had to go. So far, he says he’s been welcomed by the Ukrainians he’s met.

“We’re brothers and sisters in the fight for civilization and self-determination and sovereignty of free nations everywhere,” David said.

David has spent time on the front lines, but was recently rotated out to rest and regroup. He will lean on the inspiration of the people he’s fighting with when it is time to go back.

“One side has a reason to die and fight. The other is nothing more than a slave army,” David said.