A Shia Muslim provincial governor has been murdered in Iraq, the second in little more than a week.

Mohammed Ali al-Hassani, governor of the southern province of Muthanna, was killed this morning when a roadside bomb struck his convoy, nine days after the governor of Qadasiyah province died in another explosion.

The attacks are thought to be the product of increasing factional fighting within Shia Muslim groups battling to take control of southern Iraq. Muthanna was the first province to be transferred to Iraqi control last year.

Three other people were killed in today’s blast, and the governor's office manager and two guards seriously wounded, according to police.

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

Rethaa al-Kawaaz, spokesman for the democratic block in Muthanna, said Mr al-Hassani had been travelling to work in his armoured car when he was killed. “The security in Muthanna province is very good, there are no people killed in car bombs and no real problems. It is a very safe place. But the governor had people working against him,” he said.

“It is the same way used to kill the governor of Qadasiyah and that suggests it is the same people.”

Khalil Jalil Hamza, the Qadasiyah governor, was killed in a similar attack on August 11. He was returning to the provincial capital of Diwaniyah from a funeral for a tribal sheik when he was murdered along with Major General Khalid Hassan, the local police chief.

Both provincial leaders were members of the influential Supreme Islamic Iraqi Council (SIIC), a group led by Abdul-Aziz al-Hakim, a Shia politician, whose loyalists have been fighting against al-Mahdi Army militia for control of the oil-rich south. Violence between rival Shia and Sunni groups has often been cited as the cause of much of the violence in Iraq, but this has been accompanied by bitter intra-Shia fighting between the Islamic council and al-Mahdi Army.

Al-Mahdi Army has also been accused of targeting politicians in government buildings in Baghdad. The Shia militia, lead by Hojatoleslam Moqtadr al-Sadr, was suspected of the brazen raid on the Finance Ministry in May, during which five Britons were kidnapped. Last week dozens of gunmen in commando uniform kidnapped six senior officials from the Oil Ministry compound. The ministries of Health and Culture also have been targeted in the past two months.

The US has accused Damascus of allowing a steady flow of militants, foreign fighters and weapons to enter Iraq from Syria. Nouri al-Maliki, the Iraqi Prime Minister, travelled to Syria today for the first time in his premiership in an attempt to secure the porous border between the two countries.

Hussain al-Shahristani, the Iraqi Oil Minister, has accompanied al-Maliki on the diplomatic trip. He said he would offer to reopen a crude oil pipeline that passes through Syria if the border is made more secure.

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