The fresh wave of bombardments came as US special units were accompanying the peshmerga (Kuridsh fighters) in their drive toward the main northern city, the correspondent said.

On Thursday morning, Kurdish fighters backed by US planes clashed with Iraqi forces near an army command HQ in Khazer.

The clashes took place around 10 kilometres (six miles) from Kalak on the Mosul road from a Kurdish-held enclave in northern Iraq, first with automatic weapons fire and then mortars.

The Iraqis started the firing, after which US and British planes were called in to provide support fire, according to the Kurdish peshmerga fighters, who gave no immediate casualty figures.

The fighting eased several hours later, after the peshmerga advanced to the edge of Khazer, which lies half-way between Mosul and Kalak, on the edge of the Kurdish enclave, the correspondent said.

Iraqi soldiers had fallen back on Khazer after pulling back from Kalak last week.

The Iraqi forces fired at least 100 mortar bombs before the clash eased. US special forces, meanwhile, were also on the scene to guide in the air strikes by radio.

The fighting came as coalition-backed Kurdish groups were active on a second front, stepping up their operations around the government-held oil capital of Kirkuk, to the south of Mosul.

SPACE.WIRE