Reports from Iraq say a key ally of the US and Iraqi governments has been killed in a roadside bomb blast.

Abdul Sattar Abu Risha, who was leader of an alliance of Iraqi Sunni Arab tribes that opposed al Qaeda, was attacked near his home in the city of Ramadi, capital of Anbar.

He was among a group of leaders who met President Bush during his visit to Iraq last week and his efforts had been held up by US leaders as one of the biggest success stories in improving security after more than four years of conflict.

Police sources said he was killed by a roadside bomb however one bodyguard, who was not with Abu Risha at the time, said a bomb had been planted in his car.

Earlier today, six people were killed in separate bombings in Baghdad.

Five people were killed and eight injured when a car bomb exploded near a police patrol near the entrance to Sadr City, in north-eastern Baghdad

A roadside bomb killed one person and injured three in Baghdad's eastern Zayouna district.

Iraqi and US forces detained 12 suspected insurgents yesterday in Taji, 20km north of Baghdad.

And a policeman was killed and two others injured when their patrol was hit by a roadside bomb in Falluja, 50km west of Baghdad.

Meanwhile, 43 Iraqi detainees were freed from a US military facility today, the first day of the month of Ramadan.

The US military said it would release between 50 and 80 detainees a day during Ramadan.

Bush to offer 30,000 Iraq troop withdrawal

In Washington, Democrats have attacked President George W Bush, accusing him of failure to respond to the real situation in Iraq.

The US President is expected to endorse plans for limited cuts in troop levels in Iraq but will offer little else to Americans looking for a change of course in the unpopular war.

Mr Bush will deliver a televised address at 2am Irish time tomorrow morning, following two days of congressional testimony by his top military and diplomatic officials in Baghdad.

The proposed drawdown would not be as fast or as large as Democrats have demanded, but it could buy time for the president to pursue the war by undermining a push for a wider withdrawal.

But the White House has signaled little chance of a major shift in policy, which could make Bush's address a tough sell. Polls generally show Americans 2-to-1 against the war.

An NBC/Wall Street Journal poll found just 30% of Americans approved of his handling of Iraq, but that was an 8-point jump from 22% in July.