Baghdad: The top US military officer vowed in Baghdad on Monday that Daesh will be defeated, as Iraqi forces pressed their largest operation yet against the militants.

Some 30,000 men have been involved in a week-old operation to recapture Tikrit, one of the militants’ main hubs since they overran large parts of Iraq nine months ago.

But in a sign of the brutal lengths to which Daesh will go to maintain control, the group executed 20 men in Iraq’s northern province of Kirkuk and strung up more than a dozen of their victims’ bodies in public.

General Martin Dempsey’s visit also coincided with the start of an offensive by Kurdish Peshmerga forces in Kirkuk that further increases the pressure on the last Daesh strongholds east of the Tigris river.

“Daesh will be defeated,” Dempsey, the chairman of the US joint chiefs of staff, vowed at a news conference in Baghdad.

The United States began carrying out air strikes against Daesh in August, the first of what is now a 60-nation coalition of mostly Western and Arab states supporting Baghdad’s fightback.

The Iraqi defence minister said that his government is comfortable asking for and receiving help from Iran, a major US adversary, in its fight against Daesh.

“We are in a state of war,” Defence Minister Khalid Al Obaidi said, which requires Iraq to seek foreign assistance.

He spoke at a news conference with Dempsey.

The US worries that Iran is taking too big a role in Iraqi affairs, but Al Obaidi dismissed that notion.

“I think the situation is balanced,” the defence minister said. “The situation is acceptable to us.” He said Iran has played “a very positive role” in Iraq in helping fight Daesh.

Dempsey emphasised that strikes must “be very precise” to avoid “additional suffering,” also saying that while the priority has been protecting people, it may also be possible to use air power to defend Iraqi heritage sites being targeted by the militants.

Iraq’s tourism and antiquities minister, Adel Fahd Al Shershab, called on Sunday for the coalition to protect such sites from Daesh, after the militants smashed priceless artefacts at the Mosul museum, bulldozed one ancient city and may have attacked a second.

Dempsey stressed that training the Iraqi army, which imploded when Daesh attacked in June 2014, would take more time, as would initiatives to bring Iraq’s Sunni Arab community back into the fold.

“I do think it’s going to require some strategic patience,” he said, adding that “these underlying issues have to be resolved”.

Iraqi soldiers, police and the increasingly influential paramilitary Popular Mobilisation units, which are dominated by Shiite militias, have been closing in on Tikrit in recent days.

On Sunday, those forces retook the village of Al Bu Ajil, where some Sunni tribesmen have been accused of involvement alongside Daesh militants in the June 2014 massacre of hundreds of new, mostly Shiite recruits from the nearby base of Speicher.

The leader of the Popular Mobilisation units, Hadi Al Ameri, had described the Tikrit operation as an opportunity for revenge, sparking fears for Sunni civilians in the area.

Shiite commanders have since toned down their language and publicly urged their fighters to exercise restraint.

Dozens of families displaced by the fighting fled to Samarra, the other main city in Salah Al Deen province where Tikrit is also located, to receive assistance and be sheltered in camps.

‘Oppressed’

“I am a farmer, I left my sheep and my cows behind,” said Atta Abu Ala’a, a 50 year old who had fled with 12 members of his family from a village near Albu Ajil.

“We did not have any relations with Daesh, we were oppressed,” he said, adding that those who fled were held and interrogated by the Asaib Ahl Al Haq Shiite militia for a day before being released.

The militia’s leader, Qais Al Khazali, spoke to his fighters on the front line Sunday and urged them not to do anything that could tarnish a victory over Daesh in Tikrit, where the militants are holding out with only a few hundred men.

In the Kirkuk province town of Hawijah, Daesh executed 20 men who wanted to join the Popular Mobilisation units, a police intelligence officer and two local officials said on Monday.

The executions could not be independently confirmed, but a gruesome series of photos posted online and shared on social media are evidence that they took place.

The photos show the bodies of more than a dozen different men — said to be Popular Mobilisation members — strung by their feet from light poles, what appears to be a communications or electricity tower, and under a massive sign featuring the Daesh flag and name.

Iraqi Kurdish forces that control other areas of Kirkuk launched an operation backed by coalition air support on Monday that aims to push Daesh back south and west of the provincial capital, piling further pressure on the militants.