Hardline jihadists have captured two towns in northern Iraq after clashes with Kurdish forces, consolidating the Islamist-led insurgents’ foothold in the area.

Fighters from the Islamic State terrorist organisation took full control of the mostly Kurdish town of Zumar, northwest of the rebel-held city of Mosul, according to Kurdish officials.

The takeover on Saturday followed fierce clashes between the militants and Peshmerga – the military troops of the autonomous region of Kurdistan.

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At least 77 people from both sides were killed.

Zumar is thought to be the first Kurdish-majority town falling to the Islamic State since early June, when the al-Qaeda splinter group launched an offensive focused on Iraq’s Sunni heartland.

Meanwhile, extremist fighters seized the northern town of Kask, a seat of oil installations, after Peshmerga withdrew from it.

Iraqi government jets reportedly mounted a series of strikes on both towns following their fall to Islamists.

Iraqi forces and volunteers in Samarra. Photo: Getty

The violence triggered an exodus of civilians from the area to Kurdistan.

Zumar and Kask had been under the control of the Iraqi central government until June when insurgents led by the Islamic State pushed deep into northern and western Iraq.

At the time, Peshmerga took advantage of the collapse of Iraqi security forces and moved into several areas at the centre of a long territorial dispute with Baghdad.

Iraq has been wracked by violence over the past year, much of it blamed on the Islamic State – a radical Sunni group – and aimed at security forces and Shi’ite civilians.

According to the UN, 1186 civilians and 551 security personnel were killed in Iraq’s violence in July.