A homicide bomber on Tuesday killed at least 17 people and injured 35 after detonating his pickup truck in a market in the Iraqi northern city of Tal Afar, police said.

The casualties included civilians, police and army members and U.S. troops were on the scene assisting with the injured, according to media reports.

The attack occurred about 8:30 p.m. in the center of Tal Afar, Col. Abdul-Karim Mohammed of the Nineveh provincial police said.

The bombing occurred as vendors prepared to close for the night and the market was swarming with people finishing shopping.

Lt. Col. Ali Rasheed of Iraq's Interior Ministry said the death toll was between 15 and 20 and the attack occurred near a police station within the market area; however, the director of the city hospital, Saleh Qado, put the death toll higher, saying 20 people had died and 70 had been wounded.

U.S. medics were providing first aid to the injured on the scene before they were brought to the hospital, Qado said.

The attack occurred after incoming Prime Minister Nouri al-Maliki said he had almost finished assembling a new Cabinet, the final step in establising a national unity goverment. U.S. officials had predicted the insurgents would step up attacks to try to block the new administration.

In Amman, Jordan, U.S. Ambassador Zalmay Khalilzad said al-Maliki would soon launch a four-part plan to restore order by securing Baghdad, Basra and eight other cities, promoting reconciliation, building public confidence in the police and army and disbanding sectarian militias.

In March, President Bush touted Tal Afar, a mostly Turkomen city 260 miles northwest of Baghdad, as a success story after U.S. troops regained control there last year.

U.S. and Iraqi forces launched an operation in September aimed at cleansing the city of insurgents — the second such attempt in a year.

However, by the end of September, a female homicide bomber slipped into a crowd of recruits, killing at least six people and wounding 30.

Since then, the city has been hit by several attacks. In October, a homicide bomber plowed his explosives-packed vehicle into a crowded outdoor market, killing 30 and wounding 45.

In March, another bomber struck a joint U.S.-Iraqi military base near the city, killing at least 15 and wounding as many as 30.

A month later at least six people were killed in the city in another homicide attack.

The Associated Press contributed to this report.