Republicans said there still was no deal on how much to cut spending by government agencies for the remaining six months of the 2011 fiscal year. Democrats said a deal had been reached during overnight bargaining. Republicans, they said, were now trying to back out of that agreement to meet demands of some members in the House of Representatives who were insisting that money be withheld from Planned Parenthood, an agency that provides medical care and family planning for low-income women.

By turns House Speaker John Boehner and Senate Majority Leader Harry Reid, a Republican and Democrat respectively, went before television cameras to say a deal had not been reached, as each side sought to find shelter from blame for bringing government to a standstill. A shutdown would lock out hundreds of thousands of government workers, some estimate 800,000 or more, and cause major inconveniences for the American people. President Barack Obama said the shutdown would harm the still-fragile US economic recovery.

At issue is an ideological battle over appropriating the money necessary to keep the government operating through Sept. 30, the end of the 2011 federal fiscal year. Majority Republicans in the House of Representatives have insisted on slashing $61 billion from what was budgeted and have attached political directives that would have erased federal funds for Planned Parenthood.

Republicans apparently have dropped their insistence on slicing away money that goes to the Environmental Protection Agency for regulating greenhouse gases and other pollutants.

In the latest salvo Reid, backed by more than a dozen of his fellow Senate Democrats, said House Republicans wanted to make it harder “for women to get cancer screenings.” He was responding to a statement by Boehner earlier in the afternoon that claimed: “Most of the policy issues have been dealt with and the big fight is about spending.” Boehner wants the White House and Senate Democrats to accept a one-week stopgap bill that would fund the Defense Department for six months, cut spending by $12 billion and keep the government operating. The House passed the bill on Thursday.

“This is the responsible thing to do to support our troops and keep our federal government open,” he told reporters. He took no questions.

The White House has labeled the Republicans' one-week spending measure a distraction and said Obama would veto it.

The Democratic-controlled Senate has refused to even consider that measure. Instead the parties continue battling as temporary funding for the government expires within hours.

Obama canceled a trip to Indianapolis Friday to stay in Washington and spoke in separate phone calls with Reid and Boehner Friday morning.

But with no compromise in sight, the White House found itself in a holding pattern as the shutdown clock ticked away. The president was updated by staff on developments on Capitol Hill, and spent his afternoon in policy and national security meetings. By late afternoon, aides said there were no plans for the president to summon congressional leaders to the White House.

In another sign of the growing uncertainty over whether a deal could be reached, the president canceled a weekend trip with his family to a historical theme park in neighboring Virginia. Obama, a Democrat, has met four times this week — most recently on Thursday night — with Boehner and Reid in attempt to find a compromised. It was believed the Democrats had become willing to support cuts of nearly $38 billion for the remainder of the year, but have refused to accept the Planned Parenthood cutbacks.

Republicans, riding the wave of the deeply conservative tea party movement that swept them to control of the House in November elections, insist on deep spending cuts to tackle the spiraling US debt brought on by uncontrolled deficit spending over the last decade. This year's deficit will easily top $1 trillion, raising the debt to more than $14 trillion as the government has poured money into the economy to prevent a financial collapse and pull the nation out of the Great Recession.

Government revenues also are off because of tax cuts passed during the administration of former President George W. Bush and the initiation of programs that were not supported by tax increases or spending cuts.

Obama and the Democrats contend, with the economy just beginning to create jobs in large numbers, a shutdown would damage the recovery by putting government employees out of work. “For us to go backward because Washington couldn't get its act together is just unacceptable,” he said.

At the White House, a senior budget official said the impact of a shutdown “will be immediately felt on the economy.” Regardless of whether a deal is struck by midnight, Boehner said this fight was just the first of many likely to come as the conservative majority in the House pursues its goals of reducing the size and scope of government.

“All of us want to get on with the heavy lifting that is going to come right behind it, dealing with the federal debt and putting in place a budget for next year,” he said.

Last year, when Democrats were in charge of both houses of Congress, they failed to complete the must-pass spending bills, leaving the field clear for Republicans to attack and demand deep cuts.