A female suicide bomber wearing an explosive vest struck a checkpoint of neighbourhood patrol volunteers in Baquba, capital of Iraq's restive Diyala province, killing 10 people and wounding eight.
Police said most of the victims were mostly patrol volunteers, and many of the wounded were in serious condition.
The mainly Sunni Arab neighbourhood patrols, paid by US forces to oppose Sunni al-Qaeda militants, have frequently been targeted in recent months, and suicide bombings remain common even as overall violence in the country has declined.
Al-Qaeda leader Osama bin Laden, who is not believed to have direct control over the Iraqi militants that use his organisation's name, threatened attacks against the patrol members in an audio tape released last week.
Strikes by female suicide bombers are comparitively rare but there have been several in recent weeks in Diyala, including one which killed 16 people on December 7th and another which wounded seven people at a police station in Baquba on New Year's Eve.
Overall violence in Iraq declined dramatically over the second half of 2007. But US military figures released over the weekend show suicide bombings increased after falling to a low in October.
The past week has seen major suicide bomb attacks most days.
A bomber in a suicide vest killed 30 mourners at a Baghdad funeral on New Year's Day, the deadliest strike in the capital for months. On New Year's Eve a suicide car bomb killed 11 people including five children in a town north of Baghdad.
On Christmas day two separate strikes on neighbourhood patrol volunteers killed at least 33 people.
US forces say they have driven al-Qaeda militants out of most of the territory they once controlled, but the militants still retain the capability to stage so-called "spectacular" strikes aimed at killing large numbers of people.