Prime Minister Nuri al-Maliki on Wednesday accused Iraq's autonomous Kurdish region of harbouring jihadists, further ratcheting up tensions despite calls for leaders to unite against a Sunni militant offensive.

And in scenes reminiscent of the brutal sectarian war of 2006-2007, when tens of thousands were killed, the authorities found the bodies of 53 men who had been bound and executed south of Baghdad.

A jihadist-led offensive that started a month ago and soon overran swathes of five provinces north and west of Baghdad has displaced hundreds of thousands and heaped pressure on Maliki as he bids for a third term.

But he potentially damaged his efforts to retain the post by turning on Kurdish leaders based in the northern city of Arbil and accusing them of hosting militants behind the onslaught.

"Honestly, we cannot be silent over this and we cannot be silent over Arbil being a headquarters for Daash, and the Baath, and Al-Qaeda and terrorist operations," Maliki said, without elaborating.

Daash is the former Arabic acronym for the Islamic State (IS) jihadist group, which Kurdish forces are in fact fighting against in the north, while Baath refers to the banned party of executed dictator Saddam Hussein, whose regime killed tens of thousands of Kurds.

"They (militant groups) will lose, and their host will lose also," Maliki said on television.

The comments will likely bolster supporters of independence for the Kurdish region in northern Iraq, which plans to hold a referendum on the issue.

- United front -

Though Kurdish parliamentary backing is not necessary to form a government, the Kurds are seen as crucial to maintaining a united front against insurgents led by the IS.

Maliki's remarks were the latest example of persistent disunity among politicians despite calls from international powers and influential clerics for Iraq's leaders to form a government, more than two months after elections.

A parliamentary session last week ended in disarray as lawmakers traded heckles and threats and walked out.

Leaders typically agree key positions in a package, with the post of speaker generally going to a Sunni Arab, the premiership to a Shiite Arab and the presidency to a Kurd.

The White House said Vice President Joe Biden called Iraqi Kurdish leader Massud Barzani on Wednesday over the need to "accelerate the government formation process".

Despite telling AFP in 2011 that he would not seek a third term, Maliki vowed last week he would not bow to mounting pressure to step aside and allow a broader consensus government.

The crisis, which the UN has warned threatens "Syria-like chaos", has sharply polarised various communities and raised the spectre of a return to all-out sectarian bloodletting.

In scenes harking back to the brutal 2006-2007 period, the authorities discovered the corpses of 53 men in orchards south of Babil provincial capital Hilla, all with gunshots to the head and chest.

A morgue official said they were killed at least a week ago, but it was not immediately clear why.

- Iraqi forces regrouping -

Although attacks have taken place in Babil province since the IS-led offensive began, the area where the bodies were found was not close to the sites of other recent violence.

Iraqi forces have largely regrouped after the debacle that saw soldiers abandon their positions as jihadist-led militants conquered second city Mosul and advanced to within a short drive of Baghdad.

But while Iraq has received support, including equipment, intelligence and advisers from the United States, Russia, Iran and even Shiite militias it once shunned, efforts to battle the militants have languished.

A nearly two-week operation to retake Saddam's hometown of Tikrit has made little progress and with government forces still looking for a major victory, the jihadists of IS appear to be brimming with confidence.

And on Wednesday, militants attacked a base in the Mansuriyah area north of Diyala provincial capital Baquba, sparking hours-long clashes in which nine soldiers were killed and 38 wounded, officials said.

A few days after declaring the establishment of a "caliphate", the group's leader Abu Bakr al-Baghdadi -- second only to Al-Qaeda chief Ayman al-Zawahiri on the US most wanted list -- delivered a Friday sermon in Mosul's largest mosque.

Militants made a show of force Wednesday south and west of the northern city of Kirkuk, driving dozens of vehicles -- including some seized from Iraq's army -- with weapons and flags of the type flown by IS, sources said.

Jihadists in Iraq pose 'imminent' threat: Hagel
Washington (AFP) July 09, 2014 - Islamist militants that have swept across Iraq pose a clear and "imminent" danger to the Middle East, Europe and the United States, US Defense Secretary Chuck Hagel said Wednesday.

The Pentagon chief described the Sunni jihadists as a serious threat only days after suggesting Washington was not on the verge of any military action to help the Iraqi government in its fight with the extremists.

"Make no mistake -- and this country should not make any mistake on this, nor anyone in Congress -- this is a threat to our country," Hagel said of the militants during a stop at a US naval submarine base in the state of Georgia.

"This is a force that is sophisticated, it's dynamic, it's strong, it's organized, it's well-financed, it's competent, " Hagel told troops in remarks broadcast by the Pentagon.

"And it is a threat to our allies all over the Middle East. It's a threat to Europe," he said at the base in King's Bay.

The extremist group "may not appear to be an imminent threat to the United States," but "it is a threat to the United States," Hagel said.

"It is a ... clear threat to our partners in that area, and it is imminent," he said, without elaborating.

After launching an offensive last month, the Islamic State (IS) jihadists have overrun areas in five provinces north and west of Baghdad, raising fears of an all-out sectarian war.

President Barack Obama has sent military advisors to Baghdad to help the Iraqi army counter the militants but has so far stopped short of ordering US air strikes against the jihadists.

US officials and experts fear the extremists, who are also fighting in Syria's civil war next door, will carve out sanctuaries that could serve as training camps and launching pads for terror attacks on the West.

Hagel, who briefed US lawmakers on the crisis in a closed session on Tuesday, said that "what we are doing is assisting in every way we can to help the Iraqi people defeat the brutal fundamentalists that are attempting to not just destabilize Iraq, but essentially take control of Iraq."

The Pentagon chief acknowledged "sacrifices made by Americans" in Iraq during the grueling years of a US-led war that began with the 2003 invasion that toppled Saddam Hussein. US troops pulled out of Iraq in 2011.

Hagel said assessments of the Iraqi army by the roughly 200 US military advisors on the ground would be finished in "the next few days."