A would-be suicide bomber tackled by guards on the doorstep of a mosque in northern Iraq is a Syrian linked to Al Qaeda in Iraq, police said Saturday, detailing the capture that could provide new leads on other insurgent operations.

The details emerged a day after Ammar Afif Hamada, 19, was arrested by guards who became suspicious as he approached the main gate of a Shiite mosque in the disputed city of Kirkuk.

His capture could give authorities information about insurgent operations in northern Iraq and smuggling routes used to bring people from Syria — long considered one of the main pipelines for insurgents recruits from across the region.

It also comes as a welcome success story for Iraqi security forces, troubled by public complaints following a series of recent high-profile bombings in Baghdad and elsewhere.

According to a police officer involved in the investigation, Hamada fired a pistol at one guard who tried to stop him. Then another guard tackled him as he continued toward the mosque's main hall, grabbing the attacker's hands to prevent him from detonating an explosives belt.

The belt was packed with grenades containing about 55 pounds of explosives that were connected to the suspect's digital watch, the officer said, speaking on condition of anonymity because he wasn't authorized to release the information.

Word about the would-be bomber spread quickly inside the mosque, where Friday service was under way. Panicked worshippers started to flee, some cutting themselves on broken glass as they tried to jump through windows to escape.

Oil-rich Kirkuk has been the scene of rising tensions linked to a power struggle between the majority Kurds and Arabs.

A roadside bomb also exploded near a car and a cement mixer in a southern section of the city on Saturday, killing at least three civilians and wounding three others, according to police.

Hamada traveled from Syria to the northern city of Mosul about a week ago, then arrived Wednesday in Kirkuk, where he was moved from safehouse to safehouse in mainly Sunni areas, the police officer said.

Kirkuk police chief Maj. Gen. Torhan Abdul-Rahman Youssef confirmed the details and said Hamada has been an Al Qaeda operative in Iraq for the past four years and has confessed to participation in many operations in Diyala province and Baghdad.

Hamada, meanwhile, was being treated for serious head injuries at a hospital in Kirkuk after being beaten by guards and worshippers at the scene, police said.

Tensions have risen in Kirkuk as Kurdish leaders seek to incorporate it into their semiautonomous area, making it one of the most politically sensitive issues for Iraqi leaders and for U.S. military commanders preparing to withdraw their troops by the end of 2011.

The showdown is so volatile that Kirkuk was excluded from regional elections in January and the United Nations has offered a proposal for compromise plans.