But Mr Straw, who revealed he had been woken from his bed to be told of the US strikes, told Iraqis: "Our message to the people of Iraq is: 'We are with you, we support you in your wish to rid yourself of the terrible leadership of Saddam Hussein.'"

He told reporters: "We have been left with no option but to use force."

Mr Straw described the mood at this morning's cabinet meeting as "very sober and serious ... but one of complete commitment and support for the strategy [of] the prime minister".

He dodged questions on the specifics of the military attack, referring journalists to a statement due from the secretary of state for defence, Geoff Hoon, to the Commons this lunchtime.

Mr Straw said he had instructed government colleagues at today's cabinet not to give a "running commentary" on military manouvres, and refused to confirm whether the initial missile attacks had been intended to assassinate President Saddam.

But he specifically pledged that less civilians would be killed by the allies than would be the case if the Iraqi leader were left in place.

He said: "There will be innocent civilians killed in this conflict but the number of Iraqi civilians saved by this action will be exceed those killed."

Ahead of today's EU summit - which he and the prime minister will attend - Mr Straw admitted there were "big divisions" over Iraq.

He called the French foreign minister Dominique de Villipin his "good friend", but again attacked the French pledge to veto a second resolution. He also attacked the German foreign minister, Joschka Fischer, by name, saying his strategy for peace "would have run into the ground".

Mr Straw disclosed that the Department for International Development had been given £20m for humanitarian relief operations in Iraq, with a further £30m also available.