BBC's Jeremy Cooke in Baghdad: The attacks came in waves

Hundreds of cruise missiles have been fired into Iraq by US forces to punish the Baghdad government for obstructing the work of the United Nations weapons inspectors.

Sirens sounded the all-clear in Baghdad after nearly six hours of sustained attack ordered by President Bill Clinton to destroy Iraq's weapons of mass destruction.

American officials - and their UK counterparts - have warned that the onslaught will go on for as long as is required.

The UK Government has said that its aircraft, which were not involved in the first strikes, are now getting ready for further bombing raids.

President Clinton said the attacks were necessary because the Iraqis had continued to defy UN weapons inspectors and placed new restrictions on their work.

But Russian Prime Minister Yevgeny Primakov called the strikes "outrageous" and said the UN Security Council would meet again to discuss the crisis. China has also condemned the action.

UK Prime Minister Tony Blair: No alternative

The attack, code named Operation Desert Fox, began at 2200GMT. As well as cruise missile attacks a senior Pentagon official said Navy EA-6B attack planes struck against Iraqi air defence radars.

Iraqi doctors in Baghdad said at least five people had been killed and 30 wounded. There is no independent confirmation of this.

Saddam blasts US 'cowards'

Four separate raids were counted by witnesses in Baghdad. Reports said several missiles struck the city, one landing near one of the presidential palaces. Shortly after the attack began, Iraqi television and radio went off the air.

Up to 30 reported injured

Iraqi President Saddam Hussein accused the US and UK of cowardice for using long-range missiles instead of fighting face-to-face.

In a statement carried by the official Iraqi News Agency, he urged Iraqis to "fight the enemies of God, enemies of the nation, enemies of humanity".

As the missiles fell, Iraqi anti-aircraft batteries opened up across the city. BBC Baghdad Correspondent Jeremy Cooke said a series of deafening explosions echoed around the city, and the sky was lit up by tracer rounds and exploding shells.

One missile landed in a residential area of Baghdad, creating a big crater which filled with water from a burst water main. Reports said another had fallen inside Iran.

Avoiding Muslim holy month

Mr Clinton said the attacks were intended to protect the interests of the American people as well as the Middle East.

He said one reason why the US had acted now was to avoid launching military action during the Muslim holy month of Ramadan, which begins in a few days' time.

US Defence Secretary William Cohen announced that more air and ground forces were being sent to the Gulf. He said: "Iraq should not misunderstand our determination".

UN Secretary General Kofi Annan said he deeply regretted the military strikes.

The UK Prime Minister Tony Blair said he and Mr Clinton had "no option but to act" after more than a year of broken promises by Saddam Hussein.

The attacks were prompted by the publication of a report by chief UN weapons inspector, Richard Butler, which accused Saddam Hussein of breaking his promise on 14 November to co-operate fully with weapons monitors.

Iraqi Deputy Prime Minister Tariq Aziz said the report was full of falsehoods, and was merely aimed at justifying military strikes on Baghdad.

US Senate Majority Leader Trent Lott criticised the action even before it was formally announced.

"I cannot support this military action in the Persian Gulf at this time," he said.