A a bomb planted near a Sunni mosque in northern Iraq has killed 12 worshippers after morning prayers on a major Muslim holiday.

A bomb planted near a Sunni mosque in the oil-rich city of Kirkuk in northern Iraq killed 12 worshippers after morning prayers on a major Muslim holiday, according to Iraqi officials.

Police Colonel Taha Salaheddin said the attack occurred as worshippers were leaving the al-Qodus mosque after completing prayers for the start of the Eid al-Adha holiday, wounding an additional 24 people.

No one immediately claimed responsibility for the attack. The police sealed off the area around the mosque.

More than 5,000 people have been killed in Iraq since Al-Qaeda stepped up attacks following a deadly security crackdown against a Sunni protest camp in April.

Much of the violence tearing through Iraq is the work of the local Al-Qaeda branch, a Sunni extremist group. While it is possible that Sunni insurgents could be behind mosque attacks, hoping to stoke sectarian hatred, Shia militias may also be behind such assaults.

There are persistent fears of a return to the all-out Sunni-Shia sectarian turmoil that peaked in 2006-2007 and killed tens of thousands of people.

The latest attack came despite tight security measures imposed by security forces to prevent attacks during the four-day Eid al-Adha celebrations.

Al Jazeera and The Associated Press