Saddam or Clinton: who blinks first?

President Clinton yesterday warned of grave consequences if Iraq continues to defy the UN in refusing to allow weapons inspections by teams that include Americans . As Mary Dejevsky in Washington and Colin Brown in London report, Tony Blair signalled that Britain is ready to use Tornado jets in support of a US strike on Iraqi bases if diplomatic moves fail to get Saddam Hussein to back down.

President Clinton yesterday called on the United Nations to take "very strong and unambiguous action" to force Iraq to comply with UN weapons inspections. With the US-piloted U2 spy planes set to resume surveillance flights over Iraq today, he also warned that any attempt by Iraq to shoot them down would "not be tolerated".

At the same time Tony Blair gave a resolute message of support to Mr Clinton. The Prime Minister made it clear in a letter to the US President that Britain would support US forces in the area in military strikes. "I have no doubt that as in the past we must stand absolutely firm and absolutely together," Mr Blair said. He will reinforce Britain's determination that Saddam Hussein should comply with UN demands in a Mansion House speech on foreign affairs tonight in London.

Leaving no doubt about Britain's support for action, Mr Blair will warn Saddam: "This Government's determination to stand firm against a still dangerous dictator is unshakeable."

The US President was speaking on America's premier Sunday talk show, Meet the Press. The interview had been recorded the previous day, shortly after the end of a crisis meeting of senior officials at the White House to co-ordinate the US response. Mr Clinton was cautious, however, about advocating the use of force and continued the line pursued by senior US officials in recent days of insisting that the US wanted to work through the United Nations. Asked if a military strike was necessary, he said: "I don't want to rule anything in or out. I think ... at a moment like this ... it's very important that the President maintain all options and signal none. And that's where I want to be."

Reflecting Washington's concern not to find itself isolated in the UN, he said that the Iraqi leader needed to understand that this was "a serious business" ... and not just for the President of the United States. He appealed to Russia, France and other members of the UN Security Council to preserve a united front in dealing with Iraq.

George Robertson, Secretary of State for Defence, emphasised that the diplomatic pressure in the UN would seek to resolve the crisis but insisted that President Saddam had alienated France and Russia, the two members of the security council who were least hostile to him. "I hope a diplomatic solution will be found and I hope that he will retreat knowing that he is conflict with security council resolutions," Mr Robertson said on Sky TV.

Ministry of Defence sources confirmed that the use of Tornado jets, which were used in the Gulf War, was among the options being studied this weekend by Cabinet ministers.

Mr Blair is keen to ensure that the US does not appear isolated. Whitehall sources insisted that action would be taken with the support of the security council members. "We are going to be firm and resolute in dealing with Saddam. We are hoping for a diplomatic solution, and we are not talking about the military option at this stage," said a Foreign Office source.

Baghdad's move to exclude Americans from taking part in UN inspection teams was widely seen as a response to a split in the UN Security Council over a US motion to stiffen sanctions against Iraq.

Yesterday, Iraq prevented American inspectors from entering suspected weapons sites for the seventh day running, and the official newspaper of the ruling Ba'ath party said that anti-aircraft systems were on alert to shoot down "any hostile target, whatever its kind and nationality". Iraq had earlier defended movements of equipment and cameras at suspected weapons sites, saying that they were precautions against a US attack. But Baghdad continued to deny that Iraq had anything to hide.

The Republican majority leader in the Senate, Trent Lott, said he thought that Congress would support unilateral US military action against Iraq, though he added that this should be an option only "if the United Nations is not willing to act".