Syrian troops and militia battled on Wednesday to repel an Islamic State attack on the city of Hasaka in the northeast, and a Kurdish official said the government forces may not be able to hold off the jihadists.

Hasaka city is divided into zones run separately by the government of President Bashar al-Assad and a Kurdish administration, whose well-organized militia YPG receives air support from a U.S.-led alliance bombing Islamic State.

The YPG has dealt Islamic State heavy blows elsewhere in the northeast since early May, driving it out of swathes of the province bordering Iraq and Turkey. […]