WASHINGTON — Under the $700 billion economic bailout plan being discussed in the nation’s capital, Secretary Paulson would have significant leeway in setting standards over the pay levels of financial executives that receive assistance.

Key details emerged yesterday on how Congress would go about setting limits on executive compensation, should lawmakers accept the Bush administration’s call for a bailout fund to buy up toxic mortgage-related assets from financial institutions.

It’s uncertain whether the bailout plan, which many lawmakers say their constituents strongly oppose, will gain enough support to pass. Growing opposition among House Republicans, who oppose the unprecedented level of intervention in the markets, could sink the proposal. Democrats are hesitant to push alone for the bailout, lest the unpopular plan, which originated in the White House, come to be associated with their party.

By yesterday afternoon, growing discontent over a bailout emerged among Republican lawmakers and the proposal appeared in doubt.

Earlier, negotiators from both parties had emerged from a closed-door meeting in the Capitol declaring with confidence that the bailout would pass. How to curb limits on executive pay was one of the points on the agenda at the meeting.

The Republicans “in very general terms, wanted to go forward” on the bailout proposal, a congressional staffer familiar with the content of the discussions said. However, one lawmaker who attended the meeting, Rep. Spencer Bachus, the ranking Republican on the Financial Services Committee, issued a statement saying that the only agreement reached was “to continue discussions.”

At that closed-door meeting, key Republican leaders, including Senator Bennett of the banking committee and Mr. Bachus, reviewed a Democratic bailout proposal that had been crafted by the House Financial Services Committee chairman, Rep. Barney Frank, and the chairman of the banking committee, Senator Dodd.

As a starting point on executive pay, the proposal would forbid companies that decided to sell assets to the government from granting severance packages of any sort to departing senior executives for the next two years, a staffer said.

That prohibition applies to both “appropriate and inappropriate severance compensation,” the staffer, who requested anonymity, said.

Many lawmakers, concerned that the plan is viewed as a subsidy to Wall Street, have felt pressure to couple the bailout with limits on executive pay. The pay limits are intended to send the message that the bailout is not meant to enrich the wealthy.

Mr. Paulson, who, as Goldman Sachs’s chairman was Wall Street’s highest-paid executive in 2005, reportedly raking in more than $38 million, initially opposed limits on executive pay. He said pay limits would undermine the effectiveness of the proposal by discouraging participation.

He then told lawmakers on Wednesday that he accepted that any legislation should include pay limits, although he refused to provide details on how he wished the pay issue to be addressed. Mr. Bush, in his televised address Wednesday night, appeared to support pay limits. He said that legislation “should make certain that failed executives do not receive a windfall from your tax dollars.”

During yesterday morning’s discussions, lawmakers were not inclined to require companies that receive infusions of federal money to retrieve compensation that had already been paid out.

The staffer said that “one thing that is off the table is any type of retroactive activity.”

More generally, however, the staffer said lawmakers had agreed that Mr. Paulson would be able to “set standards” to prevent excessive executive compensation at companies that receive bailout money. It wasn’t immediately clear what those standards would be.

Under the agreement, Congress would give Mr. Paulson unrestricted access to the first $350 billion, but the final $350 billion would be contingent on Congress’s satisfaction with the first stage of the bailout program. Senator Schumer, at a hearing on Wednesday, had floated the idea of giving Mr. Paulson a smaller portion, $150 billion, to begin with.

The bill would leave it to Mr. Paulson’s discretion how to price the assets that the government would be buying or what type of market mechanism to use to purchase them, according to proposal discussed at yesterday morning’s meeting, the staffer said. Administration officials have spoken of using a reverse auction to purchase assets. Any legislation isn’t expected to get into such details.

Lawmakers, who say that some degree of Congressional oversight is essential, have not ruled out pushing for an oversight board with the authority to second-guess Mr. Paulson.

“Whether it will have cease and desist authority and some kind of intervention power hasn’t yet been worked out,” the staffer said.

Mayor Bloomberg called yesterday for quick passage of the bailout bill. To the lawmakers who have said this week that they have felt rushed by the White House to pass a bill in haste, without deliberation, Mr. Bloomberg expressed little sympathy.

“If you wanted time to do it responsibly with a lot of thought and a lot of dialogue, rather than trust an expert like Hank Paulson and his staff think is right, you should have done it before,” Mr. Bloomberg said at a City Hall press conference yesterday.

“We need to do something now,” he said.