HASAKA, Syria • The Kurdish YPG militia launched a major assault yesterday to seize the last government-controlled parts of the northeastern Syrian city of Hasaka after calling on pro-government militias to surrender, Kurdish forces and residents said.

They said Kurdish forces began the offensive after midnight to take the southern district of East Nashwa, close to where a security compound is located, near the governor's office.

The fighting this week in Hasaka, divided into zones of Kurdish and Syrian government control, marks the most violent confrontation between the Kurdish YPG militia and Damascus in more than five years of civil war. It forms part of a broader battle for control of the long border area abutting Turkey.

The powerful YPG militia has captured almost all of east Ghwairan, the only major Arab neighbourhood still in government hands.

Hasaka's governor told state media after the flare-up of violence the military had armed the YPG with weapons and tanks to fight Islamist elements but had not expected them to turn against them.

The YPG, known as the People's Protection Units and linked to Kurdish rebels who fight the Turkish state, is at the heart of a US-led campaign against the Islamic State in Iraq and Syria (ISIS) group in Syria and controls swathes of the north, where Kurdish groups associated with the militia have set up their own government since the Syrian war began in 2011.

Nato member Turkey, facing a Kurdish insurgency of its own, is concerned about attempts to extend Syrian Kurdish control westwards along its border.

Turkey is currently allowing a rebel Syrian force under the banner of the Free Syrian Army to assemble on its soil for an attack on an ISIS-held town, seeking to deny control to the YPG.

Meanwhile, Russia has stopped using an Iranian air base for strikes in Syria, Iran's foreign ministry announced yesterday, bringing an abrupt halt to an unprecedented deployment that was criticised both by the White House and some Iranian lawmakers.

Last week, long-range Russian Tupolev-22M3 bombers and Sukhoi-34 fighter bombers used the Nojeh air base, near the city of Hamadan in north-west Iran, to launch air strikes against armed groups in Syria.

It was the first time a foreign power used an Iranian base since World War II. Russia and Iran are both providing crucial military support to President Bashar al-Assad against rebels and ISIS fighters in Syria's five-year-old conflict.

REUTERS