Photo: Reuters

Islamic State (IS) militants have mounted a ferocious counter-attack in north Iraq, killing at least 19 people in and around the city of Kirkuk, the BBC reports.

They attacked government buildings, killing at least six police officers, and a power station under construction, where 13 employees died, officials say.

Twelve IS fighters also reportedly died and fighting seems to be continuing.

Government and Kurdish forces began a long-awaited operation against the IS capital in Iraq, Mosul, on Monday.

Mosul lies 170km to the north-east of Kirkuk, a multi-ethnic city claimed both by Iraq’s central government and the Kurds.

Government forces said on Friday they had regained control of a further two villages – al-Awaizat and Nanaha – south of Mosul, evacuating 65 displaced families and killing 15 IS militants.