Iraq was closer to breaking months of political limbo Thursday after a deal on the post of president paved the way for the formation of a new government.

The breakthrough came hours before a meeting in Baghdad between UN chief Ban Ki-moon and Prime Minister Nuri al-Maliki, whose government has complained it was not receiving adequate foreign support to battle jihadist-led insurgents.

The embattled premier has talked tough since the Islamic State (IS) and allied Sunni groups overran huge swathes of land last month, plunging Iraq into a crisis threatening its very existence as a unified country.

But his forces, despite some limited foreign military assistance and the mobilisation of Shiite militias, have failed to claw back lost ground, leaving Iraq's frontlines looking increasingly like the future borders of a partitioned country.

According to an unofficial power-sharing deal reached in the aftermath of the 2003 US-led invasion, the post of parliament speaker goes to a Sunni Arab, that of president to a Kurd and of prime minister to a Shiite Arab.

Salim al-Juburi was elected as speaker last week and in a late night meeting held behind closed doors in a Baghdad hotel, Kurdish lawmakers settled on their candidate for the presidency.

"Fuad Masum is the only candidate of the Kurdish blocs for the position of president," a senior Kurdish official who witnessed the vote told AFP.

Other officials confirmed that Masum, who was born in 1938 and became the first prime minister of autonomous Iraqi Kurdistan in 1992, had won the most votes.

Masum is from the Patriotic Union of Kurdistan (PUK) party of Jalal Talabani, the man he is now almost certain to succeed as head of state when parliament holds a vote.

- 'Crimes against humanity' -

Masum, whose main rival was the Western-educated Barham Saleh, was seen as the candidate most likely to please Iran, a key broker in Iraq and staunch Maliki ally.

The chamber is due to convene later on Thursday.

Ban Ki-moon, who has been touring the Middle East in a bid to quell the bloodshed in Gaza, but had not initially scheduled a stop in Iraq, is expected to highlight the fate of the 600,000 people who have been displaced since IS launched its assault on June 9.

Speaking before the UN Security Council Wednesday, Ban's Baghdad envoy Nickolay Mladenov called for a tougher global stance against the jihadist group, which last month proclaimed a "caliphate" straddling large parts of Iraq and Syria.

He said the world should "cooperate in efforts to enforce existing sanctions and hold accountable the perpetrators" of what he said were crimes against humanity committed by IS, once an Al-Qaeda offshoot that now appears to have outgrown the network founded by Osama bin Laden.

Mladenov cited "recruiting and using foreign fighters, engaging in murder, hostage-taking, kidnappings, gross human rights violations."

In the IS-held town of Sharqat, northwest of Baghdad, jihadist gunmen on Wednesday killed a female former candidate for parliament and wounded a women's rights activist, tribal and military sources said.

The bodies of eight soldiers and allied militiamen executed on Tuesday were found just north of Samarra, a Sunni-dominated city home to one of Shiite Islam's most important shrines.

In Jalawla, northeast of Baghdad, police and medics said IS executed four men because their brothers were policemen.

But three women and a child were also killed in a government air raid on Sharqat Wednesday and a hospital complex was damaged in another air strike on Mosul, a city of two million IS has turned into the Iraq capital of its state-building experiment.

According to a Human Rights Watch report released on Wednesday but before the latest strike, at least 75 civilians have died in similar raids since June 6 in four cities, including Sharqat.

Despite the billions of dollars spent on training and equipment by the United States during its eight-year occupation, Iraq's million-strong army completely folded when insurgents attacked last month.

Prime Minister Nuri al-Maliki has called on the US for help, but Washington is reluctant to boost military aid while the country's political leadership remains divided.

He is instead increasingly turning to Russia, and on Wednesday a spokesman said Defence Minister Saadun al-Dulaimi had been despatched to Moscow to seek "weapons, equipment and modern military aircraft."