A powerful member of the Iraqi parliament that is loyal to the anti-American Shia cleric Muqtada al-Sadr was killed in a carefully planned assassination in Baghdad yesterday.

A bomb hidden in a hole in the road exploded as a convoy carrying Salehal-Auqaeili and other lawmakers went past an Iraqi army checkpoint near Sadr City. It is probable that the killing was carried out by the Badr Organisation, the armed wing of the other large Shia party, the Iraqi Supreme Council of Iraq, who are long-time rivals of the Sadrists.

Mr Auqaeili was a senior member of the 30-member Sadrist bloc in the 275-member parliament. Competition between the political parties of the majority Shia community has become increasingly fierce in the lead-up to the provincial elections which are due to take place next year.

The killing of Mr Auqaeli, a 37-year-old former professor, may well lead to retaliation by the Sadrists, who are still a powerful force, particularly in Sadr City, where the Mahdi Army militia was stood down by Mr Sadr this year. The bodies of several members of Badr have been found in the area in recent weeks.

The Sadrists are also accusing the US of being behind the assassination because of their movement's opposition to the security pact between the US and Iraq. "The occupation forces sent us a message by staging this attack because of our stance against the agreement," said Ahmed al-Massoudi, a Sadrist spokesman.

Two other people also died in the blast. Falah Hassan Shanshal, who was in the same convoy as the dead men, said the group had become suspicious that there was little traffic in the area, which is usually crowded. "We hold the security forces responsible for this attack," he said. "They should be responsible for the security of the city."

The killing is part of a pattern of highly professional assassinations that have become common, replacing the mass slaughter of two years ago. There are also frequent attacks on the few Sunni and Shia returning to their old homes. Nine people who tried to do so in two towns south of Baghdad were killed yesterday, including a Sunni couple and their three children.