A child sells vegetables in the liberated area of western Mosul, Iraq, on May 11, 2017. Some displaced Iraqi civilians returned home in the liberated areas of western Mosul on Thursday. (Xinhua Photo)

MOSUL, Iraq, May 12 (Xinhua) -- Iraqi paramilitary units of Hashd Shaabi units launched an operation on Friday to free areas near the Iraqi-Syrian border from Islamic State (IS) militants, the Iraqi military said.

"The predominantly Shiite units, backed by the army's helicopters, advanced at 5:30 a.m. local time (0330 GMT) from several directions to the west to free the vast IS-held areas near the border with Syria, including the towns of al-Qairawan and Baaj," Abdul-Amir Yarallah from the Joint Operations Command said in a statement.

Abu Mahdi al-Muhandis, deputy commander of Hashd Shaabi units, said in another statement that the paramilitary units are still surrounding the IS-held town of Tal Afar, some 70 km west of Mosul, and part of the units headed to the west in carrying out the first phase of a major offensive that aims at securing the border areas with Syria.

The paramilitary units freed at least four villages and are fighting at the edges of two others around the IS-held town of al-Qairawan, which locates in the rugged sprawling area west of Tal Afar, according to the Hashd Shaabi statement.

The units and the army's helicopters destroyed at least five suicide car bombs trying to hit the advanced units, and two IS vehicles during sporadic fierce clashes with IS militants, the statement said.

The operation would enable the Hashd Shaabi units to secure the border areas between Iraq and neighboring Syria and cut off the IS supply routes between Mosul and the Syrian city of Raqqa, the capital of IS self-declared caliphate.

The operation came as the Iraqi security forces, backed by anti-IS international coalition, are carrying out a major offensive to dislodge IS militants from their major stronghold in the western side of Mosul in northern Iraq.