An American has died fighting in Ukraine after coming under attack on the eastern front, Ukraine’s military confirmed to NBC News on Monday. Timothy Griffin’s death brings the number of Americans killed in Russia’s invasion of Ukraine to “at least six,” according to NBC. Griffin was a part of the International Legion, a group of thousands of foreign volunteers who arrived in the country to help defend Ukraine, a spokeswoman for the division of Ukraine’s military told NBC News. Griffin’s unit was conducting a counteroffensive on the eastern front and he was “killed in action,” the spokeswoman, identified only under the callsign “Mockingjay,” said. Further details, including Griffin’s age, were not provided, but sources told NBC Griffin was from New York state. “Timothy’s memory will live on in his unit, in the Legion and the Armed Forces of Ukraine,” the International Legion said. The news comes days after The Daily Beast confirmed that 23-year-old Skyler James Greggs from Washington state died after reported fighting in northeastern Ukraine. Greggs was also a part of the International Legion.