BEIRUT — A German woman fighting with Kurdish militiamen was killed battling the Islamic State group in Syria, Kurdish officials said Monday — the third foreign national known to be killed fighting with Kurdish forces against the extremists in the war ravaged country.

Ivana Hoffmann, 19, died Saturday while fighting alongside the Kurdish Peoples Protection Units, known as the YPG, near the Syrian village of Tel Tamr, YPG spokesman Nawaf Khalil said.

Elsewhere in Syria, airstrikes by the U.S.-led coalition hit an oil refinery held by the Islamic State group outside the town of Tel Abyad, activists said.