Iranian-backed Iraqi Shi'ite militias say they have started an offensive against the extremist group Islamist State (IS) west of Mosul, assisting the operation to take back the city.
Jaafar al-Husseini, a spokesman for the Hizbullah Brigades, said they launched an offensive on October 29 along with other militias toward the town of Tal Afar.
Tal Afar was a Shi'ite-majority town before it fell to IS in 2014.
Husseini said Iranian forces are advising the fighters and Iraqi aircraft are providing airstrikes.
Iraqi forces launched a massive operation to retake IS-held Mosul on October 17.
The involvement of the Shi'ite militias is likely to cause alarm in Turkey as Tal Afar has a sizeable ethnic Turkmen population.
Turkish Foreign Minister Mevlut Cavusoglu said last week that his country will take measures if there is an attack against Tal Afar.
"Ethnic and sectarian balances must be taken into account in Mosul and Tal Afar," Cavusoglu was quoted as saying on October 26.
Based on reporting by AP, Reuters and Anadolu