BAGHDAD - At least 10,000 Iraqi troops fanned out in Baghdad's Sadr City yesterday, taking positions on main roads and rooftops and near hospitals in a bid to establish government control in the Shiite militia enclave for the first time since Saddam Hussein's ouster.

Success relies on whether a truce holds with fighters loyal to anti-U.S. Shiite cleric Muqtada al-Sadr.

The large force in tanks and humvees and on foot met no resistance from Sadr's Mahdi Army militia as it rolled into the sprawling district. The area is a 12-square-mile grid of avenues laid over a maze of tiny alleys forming densely populated slums that are home to two million Shiites.

The Iraqi soldiers and police passed burned-out shops and buildings pockmarked with bullet holes, signs of years of clashes. But many stores were open, and some residents came out to greet them. Some Mahdi Army fighters passed out copies of the Quran to the soldiers as a sign of goodwill.

The Iraqi flag was flying from the army vehicles in many areas of Sadr City. Numerous Iraqi tanks and armored personnel carriers were parked on street corners.

The tanks became a magnet for young children, who gathered around the heavy armor chatting and begging for drinks from soldiers. By midafternoon, the soldiers had relaxed enough to lounge on top of their tanks and talk on mobile phones, or to nap inside the vehicles.

The scenes were a stark contrast to a government offensive against Shiite militias in the southern city of Basra in March. That assault sparked a wave of Mahdi Army violence across the south and in Sadr City. Fighting in the south was eased by a cease-fire deal in mid-April, brokered by Iran, which has ties to both Sadr and the government.

Yesterday's deployment was paved by a separate truce reached last week.

Under the deal, militiamen promise not to attack residential areas or the Green Zone, but they refuse to give up their light weapons. Iraqi forces promised to try to refrain from seeking American help to restore order. U.S. military officials said they would follow the Iraqis' lead, and no American forces were involved in yesterday's operation.

The move is the latest by Prime Minister Nouri al-Maliki to impose government authority in areas controlled by armed groups. Besides the Basra offensive, a continuing sweep launched a week ago in the northern city of Mosul aims to uproot al-Qaeda in Iraq and other Sunni insurgents.

Iraqi officials say the first phase of yesterday's operation will restore security along main roads. A second part, during which Iraqi soldiers are expected to conduct intelligence-driven searches for banned weapons, is expected to start as soon as soldiers can safely navigate the streets of Sadr City.

The fragile truce's survival could depend on how forcefully the troops try to reduce the Mahdi Army's domination of Sadr City.

Already, Sadr supporters were complaining of the heavy deployment.

"We were surprised by the size of the force," Sheikh Salman al-Freiji, director of the Sadr Movement office in the district, told the Associated Press. "But their entry in such size has sparked fears that there could be violations of mosques and homes. There must be respect."

On Other Fronts

Tariq Aziz,

one of Saddam Hussein's best-known lieutenants, accused the Shiite-led government of seeking revenge during a trial yesterday over the executions of dozens of Baghdad merchants in 1992.

Chief prosecutor

Adnan Ali said Aziz and his codefendants were responsible for the merchants' deaths.

The trial deals

with the execution of 42 merchants who were accused by the Hussein government of being behind a sharp increase in food prices. They were rounded up in July 1992 from Baghdad's wholesale markets and charged with manipulating food supplies. All 42 were executed hours later after a quick trial.

During

a videoconference Monday with Prime Minister Nouri al-Maliki, President Bush apologized for an American sniper's shooting

of a Quran.

The U.S. military

said Sunday that it had disciplined the sniper and removed him from Iraq after he was found to have used Islam's holy book for target practice May 9.

- Associated Press

This article contains information from the New York Times.