WASHINGTON (AP) -- President Barack Obama says House Republicans have shut down the federal government over an "ideological crusade" against his health care law.

Obama spoke in the Rose Garden on the first day of the government shutdown. He said the longer the shutdown continues, the worse the impact will be.

The president says Republicans should not be able to hold the entire economy "hostage." He is urging them to reopen the government quickly and allow furloughed federal employees to go back to work.

The government shut down because Congress did not pass a funding bill ahead of Monday's midnight deadline for the end of the 2013 fiscal year.

The Senate today rejected the House's call to form a negotiating committee to resolve the deadlock.

Republicans who control the House are still insisting on changes to President Barack Obama's health care law as a condition for providing funding to keep the government operating. Senate Democrats and the White House are rejecting that idea.

Moments after today's Senate vote, Senate Majority Leader Harry Reid put the blame on House Republicans. He said, "The government is closed because of the irrationality of what's going on on the other side of the Capitol."

But Republicans say the shutdown is caused by the refusal of the White House to negotiate on the health care law.

Republicans say the GOP-controlled House intends to pass legislation to reopen portions of the government, including national parks and processing of claims at the Department of Veterans Affairs.

The House would also allow the government of Washington, D.C. to use its own taxpayer funds to provide services like garbage pickup, as well as keep D.C. employees on the job.

The closure of national parks is among the most visible effects of the partial government shutdown that hit the government after midnight on Monday. It would reopen gates and visitors centers at iconic parks like Yosemite and Yellowstone.

While VA hospitals remain open and veterans benefits continue to be paid, the legislation would allow claims processors to continue to work on the agency's lengthy backload of applications.

Traffic has been lighter and the subways less crowded today in Washington, on the first day of a partial government shutdown.

The White House is operating with a skeletal staff, including household workers taking care of the first family's residence, and presidential aides working in the West Wing. A groundskeeper working outside at daybreak said he was doing a job normally handled by four workers.

Outside the Capitol and its adjacent visitor center early today, there were no signs warning tourists they wouldn't be admitted for the usual tours. A Capitol Police officer standing outside an entrance said he'd be breaking the bad news to the visitors.

The Smithsonian museums website displayed a red banner noting that "all Smithsonian museums and the National Zoo are closed." On the zoo's website, panda mom Mei Xiang could be seen snuggling with her weeks-old cub through the morning, until the feed was abruptly cut off around 8 a.m. Care of the animals will continue.

The Internal Revenue Service says you must pay your taxes during the government shutdown. But don't expect any refunds.

The IRS said Tuesday it will gladly accept tax returns and payments during the shutdown. In fact, they are required by law.

But, the agency said, it will not issue any tax refunds until the government resumes normal operations.

Most Americans filed their taxes in the spring. But more than 12 million filers asked for an automatic six-month extension, and those returns are due Oct. 15.

Got questions? Sorry, IRS call centers will not be manned, though automated ones are still running.

The agency did issue a temporary reprieve to taxpayers who are getting audited. Audits will also be suspended until the government starts back up.

About two dozen couples who were planning to get married at memorials on the National Mall this month may have to make other plans because of the government shutdown.

National Park Service spokeswoman Carol Johnson said Tuesday that 24 weddings have been scheduled throughout October, including nine this week. Weddings are held at such sites as the Jefferson Memorial and the D.C. War Memorial honoring World War I veterans.

The weddings were scheduled with permits in advance but are now postponed indefinitely.

Johnson says the couples can reschedule once the government reopens.