Kurdish forces took control of a border crossing point with Syria, as Iraqi security forces fought insurgent groups trying to seize an ethnically mixed city in the country's northern province of Nineveh, military sources said Sunday.

The Kurdish forces, known as Peshmerga, took control of the crossing point of Rabia with Syria since Tuesday, after the Iraqi security forces withdrew from many parts of Nineveh province, a Kurdish security source told Xinhua.

The other side of the border crossing point, al-Yaroubiyah, has been under the control of Syrian opposition groups, the source said. 

Separately, fierce battles continued since late Saturday around the city of Tal Afar in Nineveh province, some 70 km west of the provincial capital Mosul, between Iraqi security forces, backed by groups of volunteers, and militant groups who tried to seize the city, according to a local police source.

The militants fired mortar shells, leaving at least five people killed and 35 injured, the source said.

The Sunni-majority province of Nineveh and its capital Mosul, some 400 km north of Baghdad, has long been a stronghold for insurgent groups, including Al Qaeda militants, since the US-led invasion of Iraq in 2003.

Large parts of the province are now in the hands of militant groups since last week after bloody clashes with Iraqi security forces.