Obama exasperated

"Am I exasperated? Absolutely I'm exasperated. Because this is entirely unnecessary," Obama told CNBC television in an interview before meeting the congressional leaders. "I am exasperated with the idea that unless I say to 20 million people, 'You can't have health insurance,' these folks will not reopen the government. That is irresponsible."

The US Army's top general said the shutdown was significantly harming day-to-day operations, and intelligence leaders say it is undermining their ability to monitor threats. A Federal Reserve official said it could delay the central bank's ability to assess whether its monetary stimulus efforts are still needed.

The uncertainty in Washington has forced Obama to scale back an Asia trip that was designed to reinforce US commitment to the region.

Despite the shutdown, Boehner's Republicans have failed to derail Obama's controversial healthcare law, which passed a milestone on Tuesday when it began signing up uninsured Americans for subsidized health coverage.

The government on Wednesday scrambled to add computer capacity to handle an unexpectedly large number of Americans logging onto new online insurance marketplaces.

Senate Republican leader Mitch McConnell, speaking to CNBC, described the law as a "trainwreck" that was "creating havoc across the country," and reiterated Republicans' call for a one-year delay in its implementation.

Though some moderate Republicans have begun to question their party's strategy, Boehner so far has kept them united behind a plan to offer a series of small bills that would re-open select parts of the government most visibly affected by the shutdown.

The Republican-controlled House passed and sent to the Senate on Wednesday a funding bill that would re-open the National Institutes of Health, which conducts medical research, and another bill to reopen shuttered federal parks and museums, such as the Smithsonian museums, the National Gallery of Art and the Holocaust Memorial Museum in Washington.

Both bills passed with the support of about two-dozen Democrats, who joined Republicans. The House was expected to vote Thursday on measures to fund veterans' care, the District of Colombia and the Army Reserve.

The measures are likely to be defeated in the Democratic-controlled Senate, and Obama said he would veto them if they reached his desk.

Still, they allowed Republicans to charge that their adversaries are standing in the way of help for elderly veterans and young cancer patients. "Will they now say 'no' to funding for veterans, our National Parks and the National Institutes of Health?" asked Boehner spokesman Michael Steel.

A Reuters/Ipsos poll indicated that 24 percent of Americans blamed Republicans for the shutdown, while 19 percent blamed Obama or Democrats. Another 46 percent said everyone was to blame.

Obama to meet congressional leaders for shutdown talks

Obama cancels visit amid stalemate