Iraqi forces retake three districts of IS bastion

Iraqi forces recaptured the first three districts of the Islamic State bastion Tal Afar on Tuesday, as the Pentagon chief visited Baghdad in a show of support.

Army, police and units of the Hashd al-Shaabi paramilitary coalition took "full control" of al-Kifah, al-Nur and al-Askari districts in Tal Afar, the Hashd said.

The Iraqi forces had encircled the city despite what Hashd spokesman Ahmed al-Assadi described as "intense" fighting. The militants inside Tal Afar, estimated to number around 1,000, responded with artillery fire and Assadi said the fight could last weeks.

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

They launched the offensive on Sunday to recapture Tal Afar, once a key IS supply hub between Mosul - around 70 kilometres (45 miles) to the east - and the Syrian border.

Thousands of civilians have fled Tal Afar in the two days since the start of the broad offensive backed by the US-led coalition fighting IS, according to the United Nations.

The International Organisation for Migration said its teams were "responding to thousands of civilians fleeing Tal Afar since the launch of the military campaign".

Since Friday, more than 3,000 people had arrived at two IOM emergency sites, many with just the clothes on their back, said the UN agency.

The UN refugee agency (UNHCR) said it had received some 9,000 people at the Hamman Al Alil transit centre in the past week, and it was preparing to accommodate nearly 30,000 more.

Mattis in Baghdad

US Defence Secretary Jim Mattis, who landed in Baghdad on Tuesday, said he wanted to keep the spotlight on eradicating the militants.

"Right now our focus is on defeating ISIS inside Iraq, restoring Iraqi sovereignty and territorial integrity," said the Pentagon chief, using an alternative acronym for IS.

Mattis declined to make any predictions on the battle.

"ISIS' 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 forces after their shock loss of Mosul to IS in 2014.

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