'Surrender or die': Iraqi PM warns IS fighters as his forces begin operation to retake Tal Afar

Iraqi forces have begun an operation to banish so-called Islamic State from one of their last remaining strongholds in the country.

Iraq's prime minister warned IS fighters had "no option" but to "surrender or die" as he announced the move on Tal Afar, a key town west of Mosul, in a televised address.

"The city of Tal Afar will be liberated and will join all the liberated cities," Prime Minister Haider al-Abad said early Sunday.

The operation on the Sunni extremist IS group could heighten sectarian and regional tensions as it will involve both Shiite and Sunni militiamen. Shiite militiamen sat out the operation to retake the mostly Sunni city of Mosul.

Tal Afar, which is about 90 miles east of the Syrian border, sits along a major road that was once a key IS supply route.

The city and surrounding area forms one of the last pockets of IS-held territory after the group lost Mosul, the country's second-largest city, in July.

Around 50,000 people have already fled Tal Afar as airstrikes were increased and troops built up.

"My message to (IS): you (have) no option, you either surrender or die," Mr al-Abad declared in the TV address.

"We prevailed in all battles against (IS), while (IS) faced death and defeat in all their battles."

Tal Afar was home to both Sunni and Shiite Turkmen before it fell to IS last year, with the town's ethnic Turkmen community maintaining close ties to neighboring Turkey.

Turkish officials have expressed concern that once territory is liberated from IS, Iraqi Kurdish or Shiite forces may push out Sunni Arabs or ethnic Turkmen.