Pentagon chief in Baghdad as Iraqi forces press Tal Afar

US Defence Secretary Jim Mattis arrived in Baghdad on Tuesday as Iraqi forces pressed an assault on Tal Afar, the Islamic State group's last major bastion in the country's north.

Mattis flew in for talks with Prime Minister Haider al- Abadi and other top officials, as well as Massud Barzani, president of the Iraqi Kurdistan Region, saying he wants to help keep the regime focused on eradicating IS jihadists.

"Right now our focus is on defeating ISIS inside Iraq, restoring Iraqi sovereignty and territorial integrity," Mattis told journalists ahead of his trip to Baghdad, using an alternative acronym for IS.

Iraqi troops, supported by the forces of a US-led international coalition, routed IS fighters in Mosul in July following a gruelling nine-month fight.

On Sunday they launched an assault on Tal Afar, once a key IS supply hub between Mosul -- around 70 kilometres (45 miles) further east -- and the Syrian border.

In the desert plains around Tal Afar, convoys of tanks and armoured vehicles could be seen heading Monday for the jihadist-held city, raising huge clouds of dust.

Mattis would not make any predictions on the fight.

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

(This article has not been edited by DNA's editorial team and is auto-generated from an agency feed.)