Fox News correspondent Griff Jenkins reported on the first U.S. citizen to die fighting alongside the Ukrainians on "Special Report."

GRIFF JENKINS: The war is entering day 66 here with missile strikes across the country as the White House urges Americans not to travel to Ukraine for any reason, but also offering sympathy for the Marine veteran killed on the battlefield. 

JEN PSAKI: We know a family is mourning, a wife is mourning and our hearts are with them.  

GRIFF JENKINS: 22-year-old Marine veteran Willy Cancel is the first known U.S. citizen to die while fighting alongside Ukrainians, leaving behind a wife and seven-month-old son. The Orange County, New York native was a corrections officer and working for a private military contracting company, according to his mother. Willy flew into Poland on March 12th and crossed into Ukraine the next day, unclear exactly how he died.