WASHINGTON — Congress shows no sign of heading off the first government shutdown in 17 years as House Republicans were holding firm Monday against a stopgap bill that does not in some way affect President Obama's health care law.

President Obama and Senate Majority Leader Harry Reid, D-Nev., maintain that the only way to avoid a shutdown is to approve a stopgap spending bill with no extraneous provisions on Obamacare.

House Republicans were scheduled to huddle at 2 p.m. The Senate comes in to session at the same time, and Reid is expected to quickly move to table two House-passed amendments to the spending resolution that would delay the implementation of some parts of the law for one year and to repeal a 2.3% tax on medical devices.

Much of the health care law is already in place, including provisions that expand prescription drug discounts and allow children up to age 26 to remain on their parents' health insurance policies. Tuesday is the first day for uninsured Americans to shop for and buy health insurance policies on state websites, also called exchanges.

Obama said Monday that he is not resigned to a government shutdown and that he would speak to some members of Congress later in the day.

GOP members should "set aside short-term politics and look at the long-term here," Obama told reporters after a meeting with Israeli Prime Minister Benjamin Netanyahu.

It is unclear what Republicans will do next. House Majority Whip Kevin McCarthy, R-Calif., has said the House is prepared to volley back to the Senate for a third time provisions affecting Obamacare, but Republicans have not solidified around a plan.

House Speaker John Boehner, R-Ohio, is unlikely to put the Senate-passed spending resolution to keep the government running through Dec. 15 on the House floor unless it is clear that a critical mass of Republicans will support it. House Republicans could also put forward an even shorter stopgap measure for one week or less to keep the government open and buy leaders more time.

The last time the government shut down was in 1995-1996 for a combined period of 28 days during budget standoffs between the Clinton administration and a Republican Congress. Most Americans would not feel the affects of a short-term shutdown because most essential government operations would continue, but a longer-term shutdown could negatively affect the economy and federal workers and inconvenience Americans in need of government services.

Contributing: David Jackson