Washington - Congress on Sunday was on the threshold of sealing a controversial 700-billion-dollar bailout deal intended to pull the US back from the edge of a financial meltdown.

The measure, which is intended to thaw out frozen credit lines with a government purchase of toxic mortgage assets and securities, could go for a vote as early as Monday.

Conservative Republicans in the House of Representatives were still waiting to see the final draft written by staffers who worked through the night, but they indicated they had oral agreement on some of their demands that Wall Street carry more of the plan's burden.

"We need to look and see where we are on paper tomorrow," Representative Roy Blunt, the chief negotiator for House Republicans, said, referring to Sunday afternoon.

The breakthrough was announced just after midnight by weary Congressional leaders who included Blunt, House Speaker Nancy Pelosi, a Democrat, and Treasury Secretary Henry Paulson. They said they had made "great progress" on agreement but refused to give details.

Paulson, a one-time wheeler dealer on Wall Street, said the deal would be effective in stabilizing the marketplace and protecting taxpayers "to the maximum extent possible."

"I think we're there. So far so good," he said.

It was the first time in nine days of tough negotiations and harsh words that such a high-ranking group appeared together to speak about the rescue plan.

Pelosi is pushing to get the written version posted online before markets open in Asia Monday morning.

Majority Democrats are worried about the political fallout of the unpopular bailout of Wall Street as expressed by constituents in emails and phone calls. That's why they are insisting that Republicans get solidly behind the plan proposed by their Republican President George W Bush.

With November 4 presidential and congressional elections looming, many lawmakers on both sides of the aisle will likely vote against the plan.

Two weeks of financial turmoil in the United States have played havoc with world markets. An air of frantic urgency has propelled uncertainty as Bush made nearly daily pleas to Congress and the US public to understand how near the country was to a financial meltdown.

The White House has already conceded to demands by Democrats and Senate Republicans to allow limits on executive compensation in firms being helped, to insist on partial government equity stakes in the companies, to set up a bipartisan oversight panel and to give more help for mortgage foreclosures, Pelosi said.

"For the first time in history there will be restrictions on executive salaries," Barney Frank, chairman of the House committee on finance and a key player in the negotiations, told CNN Sunday morning.

So-called golden parachutes which belong to Wall Street's excesses of past years will also be hit, Democrats said.

The two new concessions in the deal announced early Sunday morning were made in response to demands by House Republicans, two key legislators told CNN Sunday morning.

One would require Wall Street to make up the difference if the government does not recoup the 700-billion-dollar layout within five years, according to Frank and Representative Eric Cantor, a member of the House Republican leadership.

"We want to make sure Wall Street shares the pain of the plan," said Cantor.

A second concession requires the government to set up an insurance programme for Wall Street to guarantee the estimated 2 trillion dollars in mortgage assets that are performing well but could be threatened by the downward spiral of the bad loans, Cantor said.

The government hopes that the bargain basement assets it buys will appreciate in value so they can recoup their costs on the free market as the slumping housing market recovers and the number of foreclosures declines.

Paulson has even said the government could make a profit.