KIRKUK, Iraq (Reuters) - A bomb exploded near a mosque in the northern Iraqi city of Kirkuk on Tuesday, killing eight Sunni worshippers after the first prayer of the Muslim Feast of Sacrifice, or Eid al-Adha, police and medical sources said.
Insurgents usually intensify their attacks during religious holidays in Iraq, and security officials expect more violence over the coming days.
More than 6,000 people have been killed in bloodshed so far this year as Sunni Islamist and other insurgents regain ground and momentum in an onslaught against Iraq's Shi'ite-led government.
There was no immediate claim of responsibility for Tuesday's attack.
"I was on my way home nearby when I heard the explosion. I ran back to see what had happened and there were many killed and wounded people," said Ibrahim Mohammed. "There is drilling work on one of the mosque pillars and the bomb was placed there".
Fifteen people were wounded in the blast, said authorities.
Forced underground in 2007, al Qaeda's Iraqi wing has been reinvigorated by the civil war in neighboring Syria and growing resentment among the country's Sunni minority towards the Shi'ite-led government.
A raid by government security forces on a Sunni protest camp in April touched off a backlash by militants that still continues.
"These attacks, the latest in an upsurge of bombings, are particularly despicable as they hit Iraqis at a time when they extend their hands to the needy and the suffering on the occasion of Eid Al-Adha," said the spokesman for the Secretary-General of the United Nations.
(Reporting by Mustafa Mahmoud; Writing by Suadad al-Salhy; Editing by Andrew Heavens)