BAGHDAD - Kurdish fighters backed by US warplanes pushed back jihadists around Iraq's largest dam on Sunday, as Sunni Arab tribesmen and security forces fought the militants west of Baghdad.
Two months of violence have brought Iraq to the brink of breakup, and world powers relieved by the exit of divisive premier Nuri al-Maliki were sending aid to the hundreds of thousands who have fled their homes as well as arms to the Kurds.
Kurdish fighters were advancing on Mosul dam, which the Islamic State (IS) fighters seized a week ago, but their progress was being hampered by roadside bombs, Kurdish officials said.
The dam on the Tigris river north of Iraq's second city provides electricity and irrigation water for farming to much of the region.
It recapture would be the first major prize won back from the jihadists since they launched their shock offensive in early June, routing the security forces across much of northern and western Iraq.
An AFP journalist saw towers of smoke rising from the dam area on Sunday.
"Half of the Mosul dam area was retaken, the eastern part," said Kawa Khatari, an official of the autonomous Kurdish region's largest party.
"They are heading towards Tal Kayf, but the main road was planted with roadside bombs," he added.
Another Kurdish official, Harim Kamal Agha, said the bombs planted by the retreating jihadists were slowing the advance.
The US military said it carried out nine air strikes on Saturday in support of Kurdish forces.
US Central Command said warplanes and drones had destroyed or damaged four armoured personnel carriers, seven armed vehicles, two Humvees and an armoured vehicle.
Buoyed by the air strikes US President Barack Obama ordered last week, Kurdish forces have tried to claw back the ground they have lost since the start of this month, when the jihadists went back on the offensive north, east and west of Mosul.
In Anbar province, west of Baghdad, security forces backed by Sunni Arab tribal militia, who threw their weight behind a counter-offensive against the jihadists on Friday, made gains west of the provincial capital Ramadi, police said.
Fighting was also taking place near the strategic Euphrates Valley town of Haditha, which hosts another important dam, Police Staff Major General Ahmed Sadag said.
The rallying of more than two dozen Sunni tribes to the government side marked a potential turning point in the fightback against the jihadists and their allies.
The militants were able to sweep through the Sunni Arab heartland north and west of Baghdad in June, encountering little effective resistance, and Iraqi federal security forces have yet to make significant headway in regaining ground.
Anbar was the birthplace of the Sahwa, or Awakening, movement of Sunni tribes that from late 2006 sided with US forces against their co-religionists in Al-Qaeda, helping turn the tide of that insurgency.
In the north, members of minority groups including the Yazidis, Christians, Shabak and Turkmen, remain under threat of kidnapping or death at the hands of the jihadists, human rights groups said.
On Friday, IS fighters killed around 80 Yazidi Kurds in the village of Kocho near the northwestern town of Sinjar, Kurdish officials said.
The jihadist' storming of the town on August 3 sent tens of thousands of civilians fleeing into the Sinjar mountains, prompting an international aid operation and helping to trigger the launch of US air strikes.
The Yazidis' ancient non-Muslim faith is anathema to the Sunni extremists of IS.
Human rights groups and residents say IS fighters have been demanding that religious minorities in the Mosul region either convert or leave, unleashing violent reprisals on any who refuse.
Amnesty International, which has been documenting mass abductions in the Sinjar area, says IS has kidnapped thousands of Yazidis in this month's offensive.
Tens of thousands have fled, most of them seeking refuge in areas of northern Iraq still under Kurdish control, some in neighbouring Syria.
When the jihadists began their Iraq offensive on June 9, Kurdish forces initially fared better than federal government troops, many of whom simply fled.
But the US-made weaponry abandoned by the federal army has turned IS into an even more formidable foe.
Many in and outside Iraq say the Shiite-led government was partly to blame by pushing sectarian policies that have marginalised and radicalised the Sunni Arab minority.
Maliki was seen as an obstacle to any progress, and his announcement on Thursday that he was abandoning his efforts to cling to power was welcomed with a sigh of relief at home and abroad.
International support has poured in for prime minister designate Haidar al-Abadi as he attempts to forge a new, more inclusive government capable of uniting broad support against the jihadists.