The League's ambassador to the UN, Yahir Mahmasanni, told the BBC's World Today programme that a change of regime in any country must come from within.

It is very difficult in [Iraq] to have any high degree of confidence that what we will find there is what the UN said was illegal, which is weapons of mass destruction

Ken Adelman US defence advisor

Opposition to an American-led operation has grown, with French President Jacques Chirac joining Arab and Muslim leaders in urging caution.

In Denmark, European Union ministers meeting at a two-day conference are due to discuss the situation with Iraq and the possibility of US military action.

In recent days, officials in Baghdad and Washington have suggested the key issue of Iraq's refusal to readmit UN weapons inspectors has become less relevant, with Baghdad claiming America has already decided on war.

British proposal

Mr Mahmasanni said that unilateral action against Iraq would violate the Charter of the UN.

"What gives a superpower the right to change the regime of another country?" he asked.

Arab League

Set up in 1945 as a voluntary organisation of states promoting common interests Has 22 members including Iraq

"If you start changing regimes and attacking countries, where do you start? The Middle East, Europe, Latin America, Africa? Where do you stop?"

French President Jacques Chirac also called for a UN mandate to be sought for any military action.

"We are beginning to see the temptation of legitimising the unilateral and preventive use of force - this development is worrying," he told French diplomats.

"It goes against France's view of collective security, a view which relies on cooperation between states, respect for law and the authority of the [UN] Security Council."

Britain has tried to bridge the emerging gap with Washington by proposing a deadline to force Iraq to comply with UN resolutions.

Foreign Secretary Jack Straw told the Financial Times newspaper that Baghdad should be put "on the spot" over allowing inspectors to search for weapons of mass destruction.

'Too late'

Baghdad has dismissed calls to allow back inspectors - which it calls "spies" - on the grounds that the US has already made up its mind to attack.

"What purpose would there be for a goodwill gesture or an initiative for the return of spies?" said Iraqi Vice-President Taha Yassin Ramadan on a visit to Syria.

"The US administration says day and night that this issue is not related to whether the inspectors return or not, that it has to do with changing the regime by force."

The BBC's diplomatic correspondent, James Robbins, says that Iraq's new stance flatly contradicts others more conciliatory earlier in the week and it all confuses a crisis which is already alarmingly confused.

Ken Adelman, a senior adviser to US Defence Secretary Donald Rumsfeld, has told the BBC he believes the inspectors - barred from entering Iraq since 1998 - would be unable to do an effective job even if allowed back now:

"It is very difficult in [Iraq] to have any high degree of confidence that what we will find there is what the UN said was illegal, which is weapons of mass destruction."

Unnamed US officials have also been quoted in news agency reports as saying the Bush administration will seek to oust Saddam Hussein regardless of whether he allows back the inspectors.