Officials say the acting deputy governor, who is a senior Sadrist, has been arrested by Iraqi troops in the southern city of Amarah.
A provincial official says Iraqi troops arrested Rafia Abdul-Jabbar in his office Thursday morning as the government officially launched its latest operation against militias.
Abdul-Jabbar is the top city administrator in Amarah as well as acting deputy governor for the surrounding Maysan province.
The official, who declined to be identified because he wasn't authorized to release the information, says a member of the provincial council also was arrested.
Iraqi Defense Ministry spokesman, Maj. Gen. Mohammed al-Askari, has confirmed that Abdul-Jabbar is among 17 wanted people detained Thursday.
Iraqi troops fanned out across the Shiite militia stronghold of Amarah Thursday and gunmen tossed their weapons onto the streets or into canals as the government officially launched its crackdown.
The operation came a day after the expiration of a four-day deadline for militants in the city to surrender their arms or face arrest.
It's the fourth such U.S.-backed Iraqi military operation launched against Shiite and Sunni extremists in recent months as Prime Minister Nouri al-Maliki seeks to assert government control over the country ahead of provincial elections, expected in the fall.
Col. Mahdi al-Assadi, the police commander for Maysan province, of which Amarah is the capital, imposed an indefinite curfew on parts of the city but government offices, schools and colleges won't be affected, according to a government statement.
Iraqi security forces have already found large weapons caches and munitions in the run-up to the offensive, the statement said.
Iraqi troops were heavily deployed in the Tigris River city, a stronghold of anti-U.S. cleric Muqtada al-Sadr's Mahdi Army militia and the purported center of weapons smuggling from neighboring Iran.
They began search operations about 4 a.m. local time, a provincial spokesman said, speaking on condition of anonymity because he's not authorized to release the information.
About 30 gunmen handed in weapons, while others were randomly throwing them in the streets or in canals to avoid arrest, he said, adding that large weapons caches had been found hidden outside the city.
In a bid to shore up support among the local populace, recruiting centers for the Iraqi police and the army were opened in the city center.
Iraqi army reinforcements began arriving last week in Amarah, 200 miles southeast of Baghdad, to prepare for the operation.
But no fighting has been reported and Sadrist officials have said they won't put up any resistance unless government troops make arrests without warrants or commit other violations.
The Amarah operation comes as U.S. and Iraqi troops continue offensives against Shiite militias in the southern city of Basra and Baghdad's Sadr City district as well as against Sunni insurgents in the northern city of Mosul.
Iraqi troops arrested 11 people on the wanted list who were believed be members of armed groups and seized an unspecified number of weapons during overnight raids in Basra, Iraqi military commander Maj. Gen. Mohammed Jawad Huwaidi told The Associated Press.
U.S. troops also captured six suspected insurgents, including a wanted man believed to have ties to local al Qaeda in Iraq leaders, the military said. Fifteen others were captured during operations targeting al Qaeda elsewhere in northern Iraq, according to the statement.