Violence in Iraq has left at least 1,420 people dead during the month of August as Iraqi forces fought to regain areas overrun by jihadist-led militants, the United Nations has said.

At least 1,370 people were wounded during the same period, the UN's Iraq mission said in a statement.

It added that the figures do not include Anbar province.

It also said there were difficulties in verifying incidents in areas where there was fighting or which were outside government control.

Militants led by the Islamic State jihadist group overran chunks of five provinces in June, sweeping security forces aside.

After a period of largely static battle lines, the militants launched a renewed offensive in the north early last month, driving Kurdish forces back towards their regional capital, displacing hundreds of thousands of people and prompting the US to launch air strikes.

Kurdish fighters with US air support have managed to win back some of the lost ground in the north, and there has also been heavy fighting northeast of Baghdad.

Militants have also carried out a spate of bombings that have caused heavy casualties.