BEIRUT (Reuters) - 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.
Islamic State now appears intent on making up for those losses by storming government-held areas of Hasaka city, where it sees Syrian troops as a weaker adversary than the Kurds, a YPG spokesman and the Syrian Observatory for Human Rights said.
"We do not believe the regime will be able to repel the attack if Daesh is really serious about making progress towards the city," Redur Xelil, the YPG spokesman, told Reuters. Daesh is an Arabic name for Islamic State used by its opponents.
"Half the city is under our control in the north and northwest and certainly when they reach the borders of our area they will receive a stiff response," he said.
The Syrian Observatory for Human Rights, a UK-based group that monitors the war, said Islamic State used car bombs to attack government forces 2 km south of the city. State media reported fighting with Islamic State in the area and air strikes on its positions.
"It is a serious attack. An attempt to make up for other losses," Rami Abdulrahman, who runs the Observatory, said.
Steady advances by insurgents in Syria have increased military pressure on Assad, whose government increasingly sees western areas near the capital and the coast as its priority in the four-year-old conflict.
The United States accused Assad on Tuesday of aiding an Islamic State advance against rival insurgents north of Aleppo, echoing claims made by rebels that Damascus dismisses.
The northeastern corner of Syria is strategically important because it links areas controlled by Islamic State in Syria and Iraq.
State television also reported the clashes, saying they were fought around a prison under construction. Islamic State fighters tried to break into the unfinished building after setting off five car bombs, it said in a newsflash.
The Observatory, which collects its information from sources on the ground, said around 30 fighters from the Syrian military and allied militia had been killed in five days of battles with Islamic State in Hasaka province.
As he faces setbacks in more far-flung areas, Assad is seeking to shore up control over the western region including Damascus, aided by his allies in the Lebanese group Hezbollah.
Hezbollah said it had seized ground from insurgents near the Lebanon-Syria border, widening its joint offensive with the Syrian army to try to clear the area of militant groups including al Qaeda's Syrian wing.
The Iran-backed group, a crucial Assad ally, said in a statement it had seized three hilltops in the mountainous area east of the Lebanese town of Arsal, which was attacked last August by the al Qaeda-linked Nusra Front and Islamic State.
Reporting by Sylvia Westall and Tom Perry; Editing by Tom Heneghan