WASHINGTON (MarketWatch) -- The Bush administration is stepping up pressure on lawmakers for urgent action to stabilize the financial system, calling for speedy passage of its $700 billion rescue plan.

Calling the past few weeks a "humbling" time for the United States, Treasury Secretary Henry Paulson's message is that the U.S. taxpayer is at risk from the fallout stemming from the ongoing financial crisis. However Paulson, appearing on Sunday talk shows, is emphasizing that the plan to take bad mortgage assets off of companies' books will be worth the cost.

There's "much greater risk in not doing this than in doing it," Paulson said in an interview on Fox News Sunday.

"I hate the fact that the taxpayer will be at risk, but the taxpayer was already at risk," he said later on CBS's "Face the Nation."

On Monday, President Bush amplified the call to action and warned Democrats not to try to tack on "unrelated" measures that could tie up the emergency legislation the government is trying to pass.

The administration is battling calls from some Democrats to amend the plan with aid for struggling homeowners and other provisions, including a new economic stimulus plan and restrictions on executive pay. See related story.

"We want this to be clean, and we want it to be quick, and it's urgent that we get this done," Paulson said.

The plan allows the government to buy the bad debt of U.S. financial institutions for the next two years. It gives the Treasury secretary the authority to buy $700 billion in mortgage-related assets, and would raise the statutory limit on the national debt from $10.6 trillion to $11.3 trillion.

There are no plans to buy assets from hedge funds, Paulson said Sunday.

The proposal doesn't specify what the government would get in return from financial companies for the federal assistance, according to an official summary of the draft plan. Read a summary of the plan.

Lawmakers and administration officials have been huddling over the weekend to review the plan and hash out details. On Sunday, Senate Banking Committee Chairman Christopher Dodd, D-Conn., said he's hopeful Congress will approve the plan soon. But he made clear that he wants more steps taken.

"The cause of this problem is still the foreclosure crisis," Dodd said. "It needs to be part of the solution. That's not to clog this up. We need to act quickly and deliberately, and we will, in my view."

Paulson said on Fox that the plan should include "mortgage-relief components" but stopped at that.

"The biggest help we can give the American people is to stabilize our financial system right now and to prevent the system from clogging up," he said.

Obama weighs in

Meanwhile, presidential contender Sen. Barack Obama, D-Ill., also said Congress must act speedily but urged officials to protect taxpayers and tighten rules on financial companies.

"We must work quickly in a bipartisan fashion to resolve this crisis to avert an even broader economic catastrophe," Obama said in remarks prepared for delivery in Charlotte, N.C. "But Washington also has to recognize that economic recovery requires that we act, not just to address the crisis on Wall Street, but also the crisis on Main Street and around kitchen tables across America."

Republican candidate Sen. John McCain had no publicly scheduled events Sunday. On Saturday, McCain said he spoke with Paulson but added that lawmakers and officials hammering out the rescue plan should consider a proposal he has floated for a government entity to spot troubled financial companies and head off insolvencies.

In a separate action on Sunday, the Treasury offered more details about a plan to shore up money market funds. First announced Friday, the plan involves insuring any publicly offered money-market fund, both retail and institutional, that pays a fee. Sunday, the Treasury said that eligible funds include both taxable and tax-exempt money market funds and that the guarantee program covers amounts held by shareholders as of the close of business on Sept. 19. Read earlier story.

In his comments Sunday, Paulson tried to assure worried Americans about their bank and money market accounts, saying those with savings in FDIC-insured bank accounts worth $100,000 or less "won't lose a penny."