A lieutenant of Iraq's most feared terrorist leader Abu Musab al-Zarqawi (search) was captured a few days ago in Mosul, the government's national security adviser said Thursday.

Qassem Dawoud identified the alleged lieutenant only as Abu Saeed but gave no further details.

Insurgents rose up this month in Mosul, Iraq's third-largest city, in support of rebels in Fallujah, who were routed by U.S. and Iraqi forces in an offensive that began Nov. 8.

U.S. and Iraqi authorities managed to regain control of Mosul after the entire 5,000-member police force disintegrated.

Al-Zarqawi, whose Al Qaeda-linked (search) group has been responsible for numerous car bombings and beheadings of foreign hostages, including three Americans and a Briton, was believed headquartered in Fallujah. But the Jordanian-born extremist managed to escape the siege.

The United States has offered a $25 million reward for al-Zarqawi's capture — the same amount being offered for Usama bin Laden (search) and his deputy, Ayman al-Zawahiri (search).

On Thursday, the U.S. military said it detained three suspected insurgents during early-morning raids in Mosul (search). Searches in a west central neighborhood netted two people, including one identified as belonging to a terrorist cell. Another suspected insurgent was found in an eastern part of the city.