Americans are trying to come to grips Tuesday with the first shutdown of the federal government in 17 years, as 800,000 federal employees face furloughs amid a deadlock in Congress.

The federal fiscal year begins on Oct. 1, but Congress was unable to pass a budget to keep the government running as conservative Republicans in the House of Representatives tried to link any funding measure to a dismantling of the Affordable Care Act, one of President Barack Obama's key achievements.

In addition to the 800,000 workers being furloughed, another 1 million federal employees will have to work without being paid as long as the shutdown continues.

The federal government is the largest employer in the United States, with more than 2 million civilians and 1.4 million military personnel on its payroll.

Military personnel will continue to be paid during the shutdown, thanks to a bill approved by both houses of Congress and signed into law by Obama.

Washington's Smithsonian museums and the National Zoo posted "Closed" signs on Tuesday and messages apologizing to the public for "any inconvenience."

The capital and its metro area, where federal operations are concentrated, could lose up to $200 million per day if the shutdown is lengthy.

Releases of government economic reports will stop and national parks will remain closed during the shutdown, but essential services, such as mail deliveries, air traffic control, issuance of social security payments, law enforcement and security services, will not be affected.

The last shutdown of the federal government occurred in January 1996 and lasted 21 days. EFE