A group connected to Osama bin Laden's al-Qaida on Tuesday claimed responsibility for assassinating Ali al-Haidri, Baghdad governor, in a shootout, while 10 Iraqi commandos were killed in a car bombing.

The pair of audacious attacks further cast doubt on the capability of Iraqi and US forces to protect voters and high-profile officials taking part in the coming landmark elections scheduled for Jan. 30.

The Baghdad governor, who was shot dead by gunmen in a drive-by shooting yesterday morning, was the most senior Iraqi official killed by insurgents in recent eight months.

Six of his bodyguards were also killed in the ambush. Two four-wheel drive vehicles and a black BMW were seen parking beside the road in the Hurriyah neighborhood in northwestern Baghdad.

In a statement posted on an Islamic website, Abu Mussab al-Zarqawi's "Al-Qaida of Jihad in the Land of Two Rivers" said young fighters from the group killed "a tyrant and American agent."

"We warn every traitor and anyone loyal to the Jews and the Christians that this will be your fate," it added.

Haidri, a pro-US Shiite technocrat, survived another assassination attempt last September. He had predicted that the situation would be more precarious in the run-up to the parliamentary elections due on Jan. 30.

Also on Tuesday, a suicide tanker bomb exploded near an Iraqi special police base in western Baghdad, killing eight commandos and two civilians, said the Iraqi Interior Ministry.

Some 60 others were also wounded in the powerful blast, which took place around 8:45 am (0545 GMT) at a post office outside the base. White smoke could be seen billowing over the Qadisiya district.

The Martyr Brigade, affiliated with "Al-Qaida of Jihad in the Land of Two Rivers," said in a statement posted on a website that one of its members carried out the attack.

The authenticity of the two statements could not be verified independently, but the al-Qaida linked group had previously claimed responsibility for a number of deadly attacks in Iraq.

With the deteriorating situation in mind, Iraq's Sunni officials continued to push the US authority to reconsider the scheduled political process, while Shiite and Kurdish leaders insisted that the elections be held on time.

In an interview televised by Arab media on Tuesday, Iraqi President Ghazi al-Yawar urged the United Nations to study the possibility of holding elections at the end of this month. "The United Nations, as an independent umbrella of legitimacy, should really take the responsibility by saying whether that's possible or not," said Yawar.

The remarks came one day after Iraqi Defense Minister Hazem al-Shaalan suggested that a postponement is possible if the Sunni Muslim community agreed to take part.

He said he will ask Arab nations to help persuade Iraqi Sunnis to participate in the elections and the interim government could offer a delay if they require. "We want to give our Sunni brothers another chance even if this means delaying the vote," he said.

In a spectacular gathering on Tuesday, hundreds of Sunni clerics and politicians warned that holding elections as scheduled would marginalize the Sunni minority.

"Holding elections in such difficult and complex conditions will marginalize a large section of the Iraqi people, which could lead to sectarian division," said a statement issued at the meeting.