United States President Barack Obama has vowed not to allow Republicans to undermine his signature healthcare legislation as a condition to restarting the government.
The government has partially shut down after the two houses of Congress failed to agree to a new budget, with Republicans insisting on the repeal or delay of Mr Obama's health law.
"They demanded ransom," Mr Obama said.
More than 700,000 federal employees face unpaid leave, and national parks, museums and many buildings are closed, the BBC reported.
National parks have been closed, meaning a loss of 750,000 daily visitors and an economic loss to gateway communities of as much as $30 million for each day parks are shut.
The most popular tourist spots in the nation's capital have closed, with barricades going up around the Lincoln Memorial, the Library of Congress, the National Archives and all Smithsonian museums.
One of the country's most iconic monuments, New York's Liberty Island - the home of the Statue of Liberty - is among those affected by the deadlock.
Blame game
On Tuesday, Mr Obama blamed conservative Republicans in the House of Representatives for the shutdown, saying "one faction of one party" was responsible because "they didn't like one law".
"They've shut down the government over an ideological crusade to deny affordable health insurance to millions of Americans," Mr Obama said at the White House.
He insisted Congress "pass a budget, end the government shutdown, pay your bills, prevent an economic shutdown".
Republicans, meanwhile, have called for talks with the Democrats.
"Perhaps if President Obama spent less time giving hyper-partisan speeches and more time working with Congress solving problems, we wouldn't find ourselves in this avoidable situation," Rory Cooper, a spokesman for Republican House Majority Leader Eric Cantor, told the BBC.
The White House has rejected a Republican plan to fund only a few portions of the government - national parks, veterans' programmes and the budget of the District of Columbia.
Plan to veto
The Obama administration said it would veto any bill to fund the government in part.
"These piecemeal efforts are not serious, and they are no way to run a government," spokeswoman Amy Brundage said in a statement.
Mr Obama did sign a bill on Monday evening to ensure the military would be paid during the shutdown.
A spokesman for House Speaker John Boehner called the White House's position "unsustainably hypocritical".
While the Democrats and Republicans blame one another for the morass, a poll released on Tuesday suggested the American public was inclined to fault the Republican strategy.
An estimated 72% of voters oppose Congress shutting down the federal government in order to block the health law, according a poll by Quinnipiac University.
