LONDON (AFP) - Iraq's Foreign Minister Hoshyar Zebari said Thursday on jihadists who have stormed two cities were "on the run" after the security forces fought back.

Fighters from the Sunni Muslim Islamic State of Iraq and the Levant (ISIL) were, according to some accounts on Thursday, advancing on Baghdad after over-running the cities of Mosul and Tikrit in recent days.

Mr Zebari, who was attending a conference in London, admitted there had been "a serious development in the city of Mosul and Tikrit".

"But the information I have today from my capital... the situation (has) started to be reversed and the Iraqi security forces have managed to reorganise and to push them back to prevent them from taking some other important strategic installations further south of Tikrit," he told Sky News television. "Now I think they are on the run, the (ISIL) people and Al-Qaeda and the armed groups."

ISIL has spearheaded a lightning offensive, overrunning the northern province of Nineveh and significant parts of Kirkuk and Salaheddin provinces, and also moving into northern Diyala.

Mr Zebari, who was attending a conference on sexual violence in war zones, admitted the offensive was "a very, very serious disruption" for Iraq, particularly for the US-trained security forces.

"It is a setback definitely for the Iraqi security forces, who collapsed in the largest city and abandoned their weapons and equipment," he said.

"Now we are trying to overcome this, to flush these terrorists out of our major cities."

He said there were signs the jihadists were already withdrawing from Mosul because the security forces were fighting back.

"There are indications they are withdrawing from Mosul because of the counter-offensive or attack and there is a better coordination between Baghdad and the Kurdish regional government who are also pushing in the north towards certain strategic areas," he said.