BAGHDAD - Islamic State-led insurgents took control of most of the western Iraqi town of Hit in Anbar province early on Thursday, security sources and local officials said.
The ultra-radical Sunni Muslim militants have captured vast swathes of western and northern Iraq including the north's biggest city Mosul in June, as well as large areas of the east and north of neighbouring Syria.
The fall of Hit exposes the Ain al-Asad military base in the nearby town of al-Baghdadi to attack. Iraqi government forces suffered big losses after insurgents laid siege to other military camps in recent months.
"Ninety per cent of Hit has been overrun by militants," said Adnan al-Fahdawi, an Anbar provincial council member, adding that the attackers were better armed than local security forces.
An eyewitness speaking from Hit told Reuters: "Scores of militants can be seen in the town with their vehicles and weapons, I can hear shooting now everywhere."
Other eyewitnesses said the insurgents raised jihadi black flags over government buildings in Hit, and that they had seen corpses of members of the security forces in the streets.
Hit is a walled market town located some 130 km (80 miles) west of the Iraqi capital Baghdad and 30 km (18 miles) from the Anbar provincial capital Ramadi, which is largely under Islamic State control.
The security sources said they believed the attackers were Islamic State fighters, who struck first with three suicide car bombs at the eastern entrance to Hit and a police station in the town. Initial reports from Hit hospital sources said six people, including one civilian, were killed and 12 people wounded.
State television al-Iraqiya said Islamic State insurgents had occupied the mayor's office and police station and that there were heavy clashes going on between the militants and the local Sunni Albu Nimr tribe.
Deputy provincial council chief Faleh al-Issawy called on state television for the Iraqi army, which has proved little threat to IS so far, to support police forces and tribes in Hit.
Soldiers, police and local Sunni Muslim fighters were trying to stem the militant advances, the security sources said.
Most of the surrounding towns in Anbar previously fell under Islamic State control.
In Ramadi, three soldiers were killed and four wounded in a car bomb blast near the headquarters of the Iraqi army's eighth brigade, a security source said.
Six militants were also killed by an Iraqi army helicopter strike in the insurgent-controlled Tamim district of Ramadi on Thursday, another security source said.