BAGHDAD - A suicide bomber killed 15 people, including at least six U.S.-backed Sunni Arab fighters, Sunday night near a crowded outdoor market in eastern Baghdad.

At least 30 people were wounded in the attack near a checkpoint at the historic Abu Hanifa mosque, in the Sunni district of Adhamiya. Women and children were among the dead, said Abu Abed, the head of the U.S.-funded Sons of Iraq security group in Adhamiya.

There were contradictory accounts about the incident. One police officer said the male bomber was disguised as a woman and arrived on foot; another said the attacker was not dressed as a woman and arrived on a bike.

More and more, militant groups have been using female suicide bombers to evade checkpoints and security checks because custom bars Iraqi men from frisking women.

The commander at the checkpoint, Farouq abu Omar, deputy leader of the local "awakening council," and four of his men were among the dead.

At least 16 Sons of Iraq have been killed in Adhamiya since last winter when the group was founded, Abu Abed said.

He warned that Al-Qaida in Iraq was regrouping in Baghdad. "We informed American forces Al-Qaida is reorganizing, and these are the results," he said.

Abu Abed has described his group as under attack from both Al-Qaida in Iraq and fighters linked to Shiite Muslim militias, including radical cleric Muqtada al-Sadr's Mahdi Army and the Badr Corps militia.