WASHINGTON, March 2: Opposition Democrats are drafting a Senate bill that would prevent the Bush administration from launching a military strike against Iran without congressional approval.

Observers say that move reflects the fear that President George W. Bush may be preparing a military action to destroy Iran’s nuclear facilities and military installations.

Freshman Senator Jim Webb, who defeated a veteran Republican and possible 2008 presidential candidate George Allen in November’s elections, is leading the effort to draft the new legislation.

Senator Webb is a former Republican Navy secretary and decorated Vietnam veteran who opposes the Iraq war.

He intends to introduce his measure next week as an amendment to the $93.4 billion war spending bill.

Senate Majority Leader Harry Reid said on Thursday that he would support the proposed legislation to put breaks on President Bush’s powers to go to war.

"I have not read this (amendment), but I'm confident, in real generality ... that I can support” the move, Senator Reid told reporters.

Mr Webb's amendment would prohibit President Bush from spending any money on a "unilateral military action in Iran without the express consent of the Congress”.

He said there would be some exceptions, but did not detail them.

Later this month, the Senate could take up debate on a $100 billion bill to pay for continued combat in Iraq and Afghanistan.

But even before the war spending bill comes up, the Senate could hold a debate in mid-March on Iraq war policy which could be used for pushing the legislation on Iran.

Democrats say that they aren't satisfied with assurances from Secretary of State Condoleezza Rice, Defence Secretary Robert Gates and Joint Chiefs of Staff Chairman General Peter Pace that there are no plans to attack Iran.

President Bush has deployed two aircraft-carrier battle groups off Iran's coast. He also frequently denounces Iran's alleged supply of weapons to militias in Iraq, and he has issued orders to US troops there to hunt those Iranians who are causing trouble.

Besides, there are persistent reports in the US media quoting senior administration sources that an attack on Iran is under consideration, both to inhibit Iran's nuclear programme and to try to undermine its leaders.

The Bush administration, however, describes these reports as speculative, pointing out that the State Department announced this week that the US will attend a regional conference on Iraq that will include representatives from Iran and Syria.

Some observers see this as the reversal of the administration’s previous policy of not talking to either regime.

Many Democrats, however, remain sceptical about the Bush administration’s commitment to solving its problems with Iran diplomatically.

They see similarities to the build-up to the Iraq war and want to leave no doubt that the 2002 authorisation to use force in Iraq doesn't extend to Iran.