Two US soldiers and a US civilian interpreter have been been killed in Syria in an ambush by a lone Islamic State gunman, the US military has said.

President Donald Trump said Saturday that “we will retaliate” after two U.S. service members and one American civilian were killed in a Syria attack that the U.S. blames on the Islamic State group.

Defence Secretary Pete Hegseth, said: "Let it be known, if you target Americans - anywhere in the world you will spend the rest of your brief, anxious life knowing the United States will hunt you, fin...