UNITED NATIONS - U.N. weapons inspectors, who will lay down demands to Iraq today about getting back into the country, may not get the unfettered access demanded by the United States unless the Security Council alters a deal made in 1998.

The inspectors are dusting off old equipment, ordering helicopters and testing technology as the United States negotiates a new proposal for their return.

The Bush administration dismissed Iraq's offer earlier this month to accept the inspectors' unconditional return under previous U.N. resolutions. Instead, it wants a tough new resolution redesigning the inspections regime and the powers inspectors would have to enter Saddam Hussein's palaces, block his movements and break in on closed facilities during their hunt for weapons.

"This resolution that we're working on has to give the inspectors all the access they need, and there cannot be any conditions on presidential sites or sensitive sites, that just can't happen," one U.S. official said.

Hans Blix, chief U.N. weapons inspector, and Jacques Baute, head of the International Atomic Energy Agency's nuclear team, will begin two days of talks today with Iraqi experts in Vienna, Austria, to arrange for the inspectors' return.

The Iraqis are supposed to bring a backlog of reports listing items they possess that could have military purposes. The lists must disclose the locations and uses for those items.

"We're certainly aware of what happened last time," said Melissa Fleming, spokeswoman for the Vienna-based energy agency. "But we uncovered Iraq's secret nuclear program, and we dismantled it. If we get unfettered access, we will be successful again."

Although they have not been inside Iraq since 1998, inspectors are certain Iraq has a biological weapons program.

Hussein would have seven days to agree to the terms of the resolution or face military action. Under the proposal, he would then have another 23 days to report his entire arsenal.

The draft resolution would then authorize inspectors to designate "no-fly" and "no-drive" zones around areas scheduled for inspection. The resolution also would not allow Iraq to assign government guides to accompany inspectors.

Meanwhile, U.S. lawmakers have yet to settle differences about the threat posed by Iraq and how to confront it, despite White House hopes that Congress soon will pass a resolution authorizing military force to topple Hussein.

Republicans and Democrats appearing on yesterday's talk shows said they hoped a resolution would win overwhelming support even as they sparred over the United Nations' role and the severity of the threat from the Iraqi president.

GOP lawmakers, lining up behind President Bush, said it is unlikely that Hussein will allow inspectors unfettered access.

"He is not going to allow them back in because he has these weapons and materials and laboratories and he isn't about to give them up," said Sen. John McCain, an Arizona Republican.

Democrats, including House members visiting Baghdad, urged the Bush administration to work closely with the United Nations and to let inspectors resume their work.

"You don't start out by putting the gun to their head and saying we're going to shoot you if you blink," said Rep. Jim McDermott, a Washington Democrat, speaking from Iraq.

Congress may consider the resolution this week, though negotiations on terms continue.

Democrats say they will not give Bush open-ended authority and are seeking to put more emphasis on a multilateral approach.

McDermott also said Bush might mislead Americans about the threat Iraq poses. He compared the situation to that in which President Lyndon B. Johnson made misleading statements about the Vietnam War. "It would not surprise me if they came with some information that is not provable," he said.

White House spokesman Gordon Johndroe said Bush has made a "very clear case" about Iraq's actions. "The American people know he hasn't misled anyone, and the American people know he won't mislead anyone."