Iraqi security forces have detained more than 100 suspects in sweeps through Mosul to try to cripple the country's last major stronghold of Sunni insurgents, a commander said Saturday.

The offensive, which began earlier this week, is the latest attempt to break the networks of Al Qaeda in Iraq and other groups in the Mosul region in northern Iraq. But the insurgents have bounced back each time with little apparent damage to their ability to strike Iraqi and U.S. troops and their allies.

The commander of Mosul operations, Maj. Gen. Hassan Karim Khudhair, told reporters the raids were carried out under strict secrecy to avoid the escape of "wanted targets." He did not give further details.

He said more than 100 suspects were arrested and will face interrogations in Baghdad. Khudhair said the raids in Mosul were continuing.

A senior security official, speaking to The Associated Press on Friday, said more than 150 people were detained in the Mosul area. The reason for the discrepancy was not immediately clear.

The official spoke on condition of anonymity because he was not authorized to speak to media.

The Iraqi-led offensive was the first in Mosul since U.S. forces withdrew from cities in June. Maj. Derrick Cheng, a U.S. military spokesman, said U.S. troops had "very limited or no involvement at all" in the Mosul crackdown.

In February, a joint U.S.-Iraqi campaign into Mosul took more than 80 suspects but appeared to make little headway against insurgents' ability to strike. The offensive came more than a year after Prime Minister Nouri al-Maliki vowed to launch a "decisive" battle against extremists in Iraq's third-largest city.

In Baghdad, a bomb scare in Iraq's parliament Saturday forced authorities to evacuate the building, but no explosives were found, an Iraqi security official said.

The building in Baghdad's protected Green Zone was cleared after a bomb-sniffing dog indicated the presence of explosives in the main chamber. The building was fully searched and no bomb was found, said the official, who also spoke on condition of anonymity because he was not authorized to speak to media.

In April 2007, a suicide bomber detonated an explosives belt in the parliament cafeteria, killing one lawmaker.