A man standing in a line of people waiting for government paychecks in northern Iraq detonated a bomb strapped to his waist Tuesday, killing himself and at least 23 others, many of them retirees and children selling wares in a nearby market.

The devastating blast in Kirkuk wounded more than 80 people and left surrounding streets "full of blood of the wounded and killed," one survivor, Nawzad Omar, 50, said later at a local hospital.

The Ansar al-Sunna Army, one of the most violent insurgent groups in Iraq, asserted responsibility for the bombing, the Associated Press reported.

South of Kirkuk, in the town of Kenaan, a suicide car bomber killed five Iraqi soldiers at a road checkpoint, and a mortar attack left the town's police station in flames, the AP reported. And in Habbaniya in western Anbar province, police said they had discovered 24 bodies dumped in two separate areas.

The U.S. military, meanwhile, reported that two soldiers attached to a Marine unit were killed Monday near the western city of Ramadi when an explosive device struck their vehicle. Also, a roadside bombing killed a U.S. soldier Tuesday on Baghdad's south side and a Marine was killed in combat near Fallujah, west of the capital.

Kirkuk, an oil-rich city about 150 miles north of Baghdad, is home to a mix of ethnic Arabs, Kurds and Turkmens and has been the scene of frequent violence in the past two years. Under Saddam Hussein's rule, the Iraqi government expelled Kurds by the thousands and re-populated the city with Arabs. But with Hussein's ouster in April 2003 and the strong showing of Kurdish parties in national elections this year, Kurds have returned to Kirkuk and are seeking to make it the capital of an autonomous northern region.

Kirkuk's police chief, Maj. Gen. Torhan Yousif, said the bomber was carrying more than 100 pounds of explosives when he joined a line at the government-run Rafidain Bank. When he detonated the device, the explosion killed and wounded civilians, police officers and employees of local political parties. It also severely damaged the bank building and surrounding shops.

The AP reported that children and street vendors selling products including sugar and kitchen utensils were among those killed, according to Capt. Salam Zangana, an official at the hospital where the victims were taken.

"Enough killing and terrorism, enough bloodshed," cried a woman who identified herself as Umm Khalid and was looking for her son, a newspaper vendor. "We became tired and we want for God to help the Iraqi people."

Yousif said the bank and the line outside was heavily guarded, but the bomber had somehow skirted the security. "This is considered a major security flaw, for which all the security plans should be looked over again," he said.

A recent succession of grisly discoveries continued Monday when 17 bodies were found 80 miles west of Baghdad and another seven were discovered near Hit, about 95 miles northwest of the capital. None was immediately identified.

Four of the 17 bodies found by Iraqi soldiers had been beheaded, according to Abdul Munim Ahmed, a physician at a hospital in nearby Ramadi, the capital of Anbar province.

In Hit, the head of the local hospital, Ahmed Jarrallah, said two of the seven bodies discovered there were women, and both had been beheaded. A statement posted at a mosque in Hit asserted that the seven had been killed by members of the Ansar al-Sunna Army. The statement called the victims "traitors" who had "been helping the occupier fight the holy warriors" by working as private contractors who supplied cement.

Iraq's government announced Tuesday that security forces had recently captured a man who built explosive devices for roadside explosives and car bombs.

Jassim Hazan Hamadi Bazi, also known as Abu Ahmed, was described in a government statement as a key member of an al Qaeda cell who crafted and sold bombs at an electronics repair shop in Balad. Bazi was apprehended on June 7, the statement said.

Ani reported from Kirkuk.

An Iraqi soldier stands guard at the scene of a suicide blast in the northern oil center of Kirkuk, where the bomber detonated explosives strapped to his waist in the midst of a line of people waiting to claim government paychecks.