Iraqi Prime Minister Haider al-Abadi said the Baghdad government would work with Kurdish authorities to liberate the northern province of Nineveh from Islamic State militants, according to Reuters.

During his first visit to the Kurdistan region since becoming Prime Minister last year, Abadi said Baghdad and Erbil faced a common enemy and would improve ties to help confront the threat.

"Our visit to Erbil today is to coordinate and cooperate on a joint plan to liberate the people of Nineveh," Abadi said at a joint news conference with Kurdish President Massoud Barzani on Monday.

Abadi declined to lay out a timetable for the plan to retake Nineveh, of which Mosul is capital, in order not to lose the "element of surprise".

The trip comes less than a week after Islamic State militants were driven out of the city of Tikrit by Iraqi forces including Shi'ite militia, backed by coalition air strikes.

Asked about reported abuses by the Shi'ite militia, who are grouped together as Popular Mobilisation Committees or Hashid Shaabi, Abadi said it was not fair to level the accusation at the entire force.

“There’s a small group that attempts to attach itself to the Hahsid Shaabi and attack civilians and their belongings and offend the Hahsid Shaabi," Abadi said. "Our measures are to arrest these people and present them to court and we have indeed arrested.”