. >> one of our outstanding united states armed service members, marine staff sergeant lewis f cardinalof california, was killed in northern iraq as we assisted the iraqi government in dealing with isil. >> reporter: the death, the second u.s. combat fatality in the anti-isil campaign came just a day before the president arrived in cuba for a history-making meeting with cuban leader raul castro. >> it's a reminder that even as we embark on this historic visit, there are u.s. armed service members who are sacrificing each and every day on behalf of our freedom and safety. so i'm grateful to them. >> reporter: it's also a reminder that as the u.s. trying to do more to help iraqi forces, it also increases the risk to u.s. troops. he was part of a unit that quieted slipped into iraq two weeks ago. their mission was to set up an artillery base about 10 miles behind the front lines. that's where thousands of iraqi forces have begun to amass in an offensive, and where u.s. advisors are helping to plan and coordinate the eventual attack. they wanted to keep the unit under wraps until it was ful