BAGHDAD - A roadside bomb Monday killed the governor of the predominantly Shiite Muthanna province, police said, the second assassination of a top provincial official in just over a week.

Police blamed the Mahdi Army, which is nominally loyal to radical Shiite cleric Muqtada al-Sadr and has been involved in several recent clashes with its political rivals.

Two bombings also struck the Shiite district of Sadr City and a busy market district elsewhere in Baghdad, killing at least six people and wounding more than 20.

Al-Sadr, meanwhile, predicted that the government of Prime Minister Nouri al-Maliki is nearing its end, tainted by its close work with U.S. forces, a British newspaper reported.

Al-Maliki arrived in Syria for his first visit to the neighboring country since he took office in May 2006. It comes amid U.S. allegations that Syria is allowing foreign fighters to cross its borders and as Damascus struggles with an influx of Iraqi refugees.

"We will discuss the serious security file and its challenges, which concern not only Iraq but the whole region. We will discuss the Iraqi community and immigrants in Syria and the ways to provide them with services," al-Maliki said.

French Foreign Minister Bernard Kouchner met with President Jalal Talabani, Kurdish leader Massoud Barzani and other Iraqi officials in the first visit by a senior French official since the start of the war set off years of icy relations between Paris and Washington.

"It is true that in the past, we did not agree with certain countries about the events in 2003, but all that has been put behind us now," he said at a joint news conference with Talabani.

Kouchner said the United Nations could play a key role in finding a political solution among Iraq's squabbling factions, warning "we cannot get used to the violence in Iraq."

Talabani promised to show Kouchner a "complete picture" of the situation in Iraq.

Muthanna Gov. Mohammed Ali al-Hassani was killed when the SUV he was riding in was struck by a bomb about 9 a.m., shortly after the convoy left his home in Rumaitha for his office in the provincial capital of Samawah, about 230 miles southeast of Baghdad.

Al-Hassani, his driver and a guard were killed, police said.

A curfew was immediately clamped on Samawah and new checkpoints erected.

On Aug. 11, the governor and police chief of another southern province, Qadasiyah, also were killed in a roadside bombing.

Both governors were members of the influential Supreme Islamic Iraqi Council, whose loyalists have been fighting the Mahdi Army militia for control of the oil-rich south as British-led forces gradually withdraw.

Al-Hassani, 52, was from a prominent clan in the area and had been governor for about two years despite several attempts by rivals in the provincial council to oust him.

"There was nothing against the governor inside the province except the confrontations between Mahdi Army and SIIC, which have claimed the lives of dozens of people," an officer said, speaking on condition of anonymity because he feared retribution.

Al-Maliki's said it had ordered an investigation and calling for restraint against retaliation: "Those behind this horrible crime want to flood the province with chaos and insecurity."

At least five provincial governors have been killed in Iraq. Three of those were killed in 2004 and 2005, apparently as part of the insurgency that frequently targets government officials and security forces as allies of the U.S.-led coalition.

The killings of al-Hassani and the Qadasiyah governor underscore the complexity of the challenges facing Iraq as Shiite militias and Sunni extremists often target not just Americans but also rivals in their own sects in Iraq's 18 provinces.

Al-Sadr told the British newspaper The Independent that al-Maliki's government was on the brink of collapse, despite efforts to bolster its base of support.

"The prime minister is a tool for the Americans and people see that clearly. It will probably be the Americans who decide to change him when they realize he has failed. We don't have a democracy here, we have a foreign occupation."

Al-Sadr also said British forces have been defeated.

"The British have given up and they know they will be leaving Iraq soon," al-Sadr was quoted as saying. "They are retreating because of the resistance they have faced."

About 500 more British troops will be pulled out within weeks, defense officials said in London. That will leave around 5,000 British soldiers, based almost exclusively at an airport camp on the fringes of the southern city of Basra.

Since February, about 1,500 British troops have pulled out under plans drawn up by former Prime Minister Tony Blair.

Prime Minister Gordon Brown plans to decide on additional troop withdrawals once U.S. Gen. David Petraeus delivers his report on Iraq next month, a Downing Street spokeswoman said.

The Bush administration is facing a Sept. 15 deadline to report to Congress on progress in Iraq as a result of the infusion of 30,000 more U.S. troops. American public opinion and congressional sentiment is running against the U.S. effort.

In another sign of growing Shiite discontent, thousands rallied against the U.S. in Sadr City, waving Iraqi flags and shouting "No, no to America." One group set a replica of an American flag on fire, then stomped on it.

The protesters want an end to the raids that are often carried out by U.S. and Iraqi forces against suspected militia fighters in Baghdad's main Shiite district. Iraqis often claim civilians are killed in the raids, and some carried photos of victims.

A car packed with explosives struck the district hours later, killing four, police said. Earlier Monday, a bomb planted on a motorcycle struck a busy market district elsewhere in the capital, killing three, police said. The officials spoke on condition of anonymity because they weren't authorized to release the information.