KIRKUK, Iraq (Reuters) – Mourners poured into mosques in Iraq's northern city of Kirkuk Friday, vowing not to let the worst bomb attack in months turn ethnic tensions into bloodshed.

Fifty people were killed and some 100 wounded in the suicide bombing Thursday of a restaurant north of the city that is disputed by Kurds, Arabs and Turkmen. It has been an oasis of relative calm during Iraq's wave of sectarian violence followed by U.S occupation.
“What is their sin?” said Miaad Ridha Mohammed, 45, a Kurd, breaking into tears before the funeral in a Sunni mosque for his brother, his brother's wife and two of their three children, all killed in Thursday's blast near Kirkuk.
Only his brother's two-year-old daughter Mina survived the bomb in a popular eatery north of Kirkuk, the bloodiest attack in Iraq since a Baghdad truck bomb killed 63 people in June.
The explosion reminded Iraqis of the fragility of a recent, decline in the sectarian slaughter prompted by the U.S.-led invasion in 2003.
The security gains will be tested when Iraq holds provincial elections in January and a general election later next year, and when U.S. troops start to pull out of cities in the first half of 2009, ahead of a full withdrawal by the end of 2011.