BAGHDAD — Followers of the anti-American cleric Moqtada al-Sadr signaled yesterday that they won’t resist a military crackdown in one of their last southern strongholds unless government troops make arrests without warrants or commit other violations.

The statements came three days before the expiration of a deadline for gunmen in the Sadrist stronghold of Amarah, the capital of Maysan province, to surrender their weapons and renounce violence or face harsh measures.

Prime Minister al-Maliki, himself a Shiite, has sent American-backed Iraqi troops to Amarah, a stronghold of Mr. Sadr’s Mahdi Army militia and the purported center of weapons smuggling from Iran. The bid to clamp control on the city follows similar efforts in the Shiite areas of Basra and Baghdad’s Sadr City and the northern Sunni insurgent bastion of Mosul.

Iraqi troops have fanned out en masse in the Tigris River city of some 450,000 people, 200 miles southeast of Baghdad, erecting new checkpoints and stationing tanks and Humvees on bridges in preparation for the operation.

But no fighting has been reported, in contrast to the fierce resistance that met the start of a government offensive in late March in Basra. That fighting spread to Sadr City before the cleric announced a series of cease-fires.

The Sadrist governor of Maysan province said local officials have expressed their support for “the imposing law operation,” to begin later this week.