Summary executions and extra judicial killings contributed to bringing the number of people killed in Iraq in recent weeks to a staggering total of at least 1,075, the UN said.
The UN human rights team in Iraq said that most of the victims are civilians who were caught up in ethnic violence exacerbated by a Sunni militant offensive led by the Islamic State of Iraq and the Levant (Isis).
"This figure — which should be viewed very much as a minimum — includes a number of verified summary executions and extra-judicial killings of civilians, police, and soldiers who were hors (de) combat [outside of combat]," said UN human rights office spokesman Rupert Colville.
The UN said that at least 757 civilians were killed in the provinces of Nineveh, Diyala and Salah al-Din provinces from June 5-22, after they fell under Isis control.
Some 599 people were reported injured in the same areas. Colville said the toll also includes casualties from shelling and crossfire.
The UN said that in the same period another 318 people were killed and 590 injured in the capital of Baghdad and areas in the south, many of them from at least six separate car bombings.
Colville said the human rights team was also verifying "a number of alleged violations that have been taking place in Iraq" since Isis advances.
Isis took over parts of Fallujah and Ramadi earlier this year and swept through Iraq from the north at the beginning of June, facing little or no resistance from government forces that abandoned some key areas of the country.
Last week, after seizing several cities in northwest Iraq, the Islamist group claimed it captured and massacred 1,700 Iraqi soldiers.
"Tragically some of those who have been abducted have been subsequently found dead and summary executions also apparently continue to take place," Colville said.