UNITED NATIONS (AP) - The United States claimed progress yesterday in its campaign for a March 17 ultimatum threatening war against Iraq, but refused to rule out delaying or abandoning a Security Council vote if necessary.

The different options reflected the turmoil in negotiations on a new Iraq resolution. After weeks of talks, the Bush administration and co-sponsors Britain and Spain were still searching for a winning formula.

Britain, a key ally, proposed a "to-do" list for Saddam Hussein - six steps to avert war including a television appearance renouncing weapons of mass destruction - in hopes of gaining votes for the resolution, which faces the threat of French and Russian vetoes.

During a tense three-hour meeting of the bitterly divided council, Britain went even further, offering to abandon the March 17 ultimatum if members approved its list of disarmament tests for Saddam. The resolution would then implicitly threaten Iraq with "serious consequences" if it failed to comply.

"This is a trial balloon, if you like, to see whether this is a way out of our current difficulties ... to see if we can keep the council together," said Britain's U.N. Ambassador Jeremy Greenstock.

Britain is desperate to get U.N. approval for military action to avert a political uproar that threatens the career of Prime Minister Tony Blair. British diplomats had initially expected the United States and Spain to co-sponsor the demands to Saddam, just as they had co-sponsored the resolution - but they didn't.

U.S. Ambassador John Negroponte said he "commended the proposal" to the council for consideration, but wanted to see how members reacted "before we embrace it in its entirety."

If the council starts to rally around the so-called benchmarks, Negroponte said, the United States would be prepared to accept "a very, very, very brief extension" of the March 17 deadline for Iraq to complete the disarmament tests.

Otherwise, he said, last week's resolution with the March 17 ultimatum for Saddam to prove he is disarming or face the threat of military action remains before the council.

Based on public statements and private interviews with senior diplomats, The Associated Press has determined that the resolution currently has the support of seven countries: Britain, the United States, Spain, Bulgaria, Cameroon, Pakistan and Mexico. Angola and Guinea were still uncommitted yesterday. Chile, Germany and China are expected to abstain. Russia could also abstain or vote against the draft along with Syria and France.

Russia and France have led the opposition to any resolution that has an ultimatum and authorizes war, and both countries indicated the British proposal did not change their position.

"It's still about war and peace," said Russia's U.N. Ambassador Sergey Lavrov. "We are not convinced that this proposal takes care of our concerns. We will study it, but we see automaticity still there."

French Ambassador Jean-Marc de La Sabliere said the British proposal didn't change the draft resolution, "which authorizes the use of force - this is what is at stake."

Diplomats said the divisions in the council were evident during the closed-door meeting, and the British proposal raised many questions. The council scheduled another meeting for this afternoon.

President Bush spoke with Blair and Spanish Prime Minister Jose Maria Aznar late yesterday to discuss strategy.

Asked if the United States would consider pulling the resolution or delaying the vote _ an option raised earlier yesterday by co-sponsor Spain - a senior administration official would not rule it out.

The official made clear that a vote, if held, would be on the U.S.-British-Spanish resolution introduced last week. The British proposals are in a side letter that is being kept separate, the official said.

It was not clear when a vote would be held, though the Americans still insisted that it come this week, possibly tomorrow.

"I wouldn't deny we are making progress, but I wouldn't lead you to believe we've got it in the bag," spokesman Richard Boucher told reporters at the State Department.

Bush and Secretary of State Colin Powell worked the phones throughout the day, calling foreign capitals in search of backing. The White House said Bush spoke with the leaders of Pakistan, Chile and Mexico, considered key swing votes, among others.

He also spoke with Russian President Vladimir Putin on a day when Alexander Vershbow, the U.S. ambassador to Russia, told the Izvestia daily "there will be damage" to U.S.-Russia relations if Moscow vetoes the resolution.

He said the casualties would include expanded energy cooperation and investment, joint work in security and anti-terrorism programs, and partnership in space.

But Russia's Lavrov said again that Moscow believes inspections are working and should not be interrupted.