BAGHDAD — Pentagon chief Jim Mattis held talks in Baghdad Tuesday to show US support for Iraqi forces as they pressed an assault on Tal Afar, Daesh (the so-called IS) group's last major bastion in the country's north.

Mattis said he wanted to keep the spotlight on eradicating Daesh militants, in remarks before going into meetings with Prime Minister Haider Al-Abadi and other top officials.

"Right now our focus is on defeating ISIS (Daesh) inside Iraq, restoring Iraqi sovereignty and territorial integrity," the US defense secretary said.

Iraqi troops, supported by the forces of a US-led international coalition, routed Daesh in Mosul in July after a grueling nine-month fight for Iraq's second city.

They launched an offensive on Sunday to recapture Tal Afar, once a key Daesh supply hub between Mosul — around 70 km to the east — and the Syrian border.

The militants inside Tal Afar — estimated to number around 1,000 — responded with artillery fire as the Iraqi forces massed outside the city

"The assault was launched on the city itself," said Ahmed Al-Assadi, spokesman for the Hashed Al-Shaabi Shiite-dominated paramilitary coalition that has been fighting Daesh alongside government forces.

Units of the Hashed, army and police had encircled the city despite what Assadi described as "intense" fighting. He said the fighting for the city would likely last weeks.

Mattis declined to make any predictions on the battle.

“Daesh’s days are certainly numbered, but it's not over yet and it's not going to be over anytime soon," he said.

Iraqi forces had "fought like the dickens in Mosul, (it) cost them over 6,000 wounded, somewhere over 1,200 killed," he noted.

Yet that comeback restored the confidence of the Iraqi security forces after their shock loss of Mosul to Daesh in 2014.

Mattis stressed that retaking Mosul would not have happened "without... Abadi's steady hand" but also thanks to extensive US support.

The future of that support still must be settled, and there would be resistance from Shiite militia and Iranians, said Nicholas Heras, Middle East Security Fellow at the Center for a New American Security in Washington.

Mattis will also meet in Arbil with Massud Barzani, president of the Iraqi Kurdistan region.

Mattis had said his discussions in Iraq would focus on the way ahead, including how to keep the country from again politically fragmenting or falling further under Iran's influence.

"Secretary Mattis is going to be very much focused on a pathway for the United States to continue to have to a residual force in Iraq to continue to train Iraqi security forces" and avoiding a successor from Daesh rising up, said Heras.

A key issue is Iraqi Kurdistan's plan for an independence referendum on Sept. 25, strongly opposed by the US as an event that could undermine Abadi and distract from the fight against Daesh.

"A referendum at this time would be potentially catastrophic to the counter-Daesh campaign," said Brett McGurk, the White House envoy to the anti-Daesh coalition.

"It's not just the United States; every member of our coalition believes that now is not the time to hold this referendum." — AFP