President Barack Obama scolded Congressional Republicans in a terse speech from the White House briefing room, just seven hours before the federal government was set to shut down for the first time in 17 years.

"You don't get to extract a ransom for doing your job," Obama said, calling out a Tea Party faction in the House of Representatives that has insisted on using the government-funding debate to make changes to the Affordable Care Act.

"One faction of one party in one house of Congress in one branch of government doesn't get to shut down the entire government just to re-fight the results of the election," he said.

Obama's statement came right before he was scheduled to hold a Cabinet meeting, which will likely focus on preparations for a government shutdown.

The government is likely to hit the deadline at midnight, as Congress has moved no closer to an agreement Monday that will keep the government funded.

The Democratic-controlled Senate tabled two amendments in the House of Representatives' version of the continuing resolution that made changes to the Affordable Care Act. The House has responded by offering a plan to pass two new amendments that chip away at Obamacare.

Obama pointed out that the Affordable Care Act will continue to be implemented "no matter what Congress decides to do today." Insurance exchanges, he said, are open on Tuesday.

"You can't shut it down," he said.

He took no questions from reporters.

Obama also noted some of the more practical effects of the shutdown, which he said would have a "very real economic impact on real people, right away":