US and British forces have begun a fourth night of air strikes and missile attacks on Iraq.

The BBC's Jeremy Bowen reports on the 4th night of bombing in Baghdad

Baghdad came under attack around 1830GMT, with at least one missile hitting the northern outskirts of the city, witnesses said.

Other reports said smoke could be seen rising from a building in the centre of the city. Iraqi anti-aircraft fire lit the night sky during the attack.

Iraqi women outside the UN headquarters in Baghdad

As the raids got under way, the US Congress voted to impeach President Bill Clinton, who is commander-in-chief of the US military.

Despite the new strikes, the Iraqi authorities remained defiant. Vice President Taha Yassin Ramadan said Iraq would fight until its last citizen. He also said Iraq would no longer work with the UN weapons inspectors.

The BBC's Rageh Omaar: Iraq says that "UNSCOM is finished"

A US spokesman earlier said the inspectors might not be able to return to Baghdad, but the US could assess Iraq's capabilities through 'technical means' and the enormous amount of information already gathered.

The US and UK made clear that military action would continue until they had achieved their objectives of damaging Iraq's ability to make weapons of mass destruction and threaten its neighbours.

However they went out of their way to try to bolster support for military action and said they were sensitive to the Muslim holy month of Ramadan, which began on Saturday.

Raids defended

UK Prime Minister Tony Blair: "We have done very serious damage"

UK Prime Minister Tony Blair said consideration for the Islamic world had led the coalition to launch strikes before Ramadan, but that military objectives had to be completed.

Earlier, he told the BBC Arabic Service that Britain and the US had no quarrel with the Iraqi people, and that any civilian casualties were deeply regretted.

In a televised address to the Arab world, President Clinton said the strikes were in the best interests of the Middle East. He said President Saddam Hussein was a threat to neighbouring countries.

However many people across the region protested against the raids. Egyptian President Hosni Mubarak called for an immediate halt, while in the Syrian capital Damascus, the US embassy was attacked by hundreds of stone-throwing demonstrators.

There were also protests in Jordan, the West Bank, Indonesia, Malaysia and the UK.

'Some success'

Footage of attack from UK Tornados

The US and UK have said they are on course to meet their objectives. Mr Blair also said the two countries were already engaged in discussions with other nations on a long-term strategy of stability and containment.

UK military sources said air strikes hit 100 targets on the first three nights, inflicting major damage on Iraq's chemical and biological weapons capability.

Iraqi hospitals have been treating casualties

Targets damaged included the headquarters of the elite Republican Guard. One-third of sites attacked related to weapons of mass destruction, another third to Iraq's air defence system, 20 were overall control facilities and the remainder military locations, they said.

Iraq acknowledged that some military buildings had been hit, but it also accused Britain and the US of targeting civilian areas.

It said hospitals and health centres had been struck. Reporters said damage they had seen on civilian buildings had been caused by shock-waves from nearby explosions.

The Iraqis also said they had held a mass funeral for 68 people killed in the three sets of raids on Baghdad.

The BBC's Jeremy Cooke: "Some targets were hit by 3 or 4 missiles"

On Friday night, the city suffered its heaviest bombardment of the campaign. It was shaken by a series of huge explosions as at least 20 cruise missiles hit in a single wave.