WASHINGTON — The US government shutdown is nearing its two-week mark with growing chaos, as the administration began mass layoffs, and air travel was disrupted by air traffic control shortages across the country.

Seeking to ease one pressure point, US President Donald Trump directed the Pentagon to use "all available funds" to pay US troops despite the funding lapse, even as hundreds of thousands of civilian workers remain furloughed and unpaid amid an escalating political standoff.

The Centers for Disease Control and Prevention notified some 1,300 employees they would be laid off — then rescinded hundreds of those notices within hours, Reuters quoted a person familiar with the matter as saying.

The US administration is set to lay off entire offices and hundreds of CDC workers as part of mass job cuts during the federal shutdown, four sources told Reuters on Saturday.

The White House and CDC did not immediately respond to requests for comment.

Trump on Friday blamed Democrats for the latest round of layoffs, which extend across the US government, following through on his shutdown-related threats.

Job cuts were under way at the Treasury Department, the US health agency, the Internal Revenue Service and the departments of education, commerce, and Homeland Security's cybersecurity division, spokespeople said, but the total extent of the layoffs was not immediately clear.

Roughly 300,000 federal civilian workers had already been set to leave their jobs this year due to a downsizing campaign initiated by Trump earlier this year.

"They started this thing," Trump told reporters during an event in the Oval Office, calling the job cuts "Democrat-oriented".

Republicans hold majorities in both chambers of Congress, but need Democratic votes in the US Senate to pass any measure that would fund the government.

Republicans are proposing an extension of the current budget, with the same spending levels, while Democrats are calling for an extension of subsidies for health insurance for low-income households.

Democrats said they will not cave to Trump's pressure tactics.

"Until Republicans get serious, they own this — every job lost, every family hurt, every service gutted is because of their decisions," Senate Democratic Leader Chuck Schumer said.

Labor unions representing federal workers have sued to stop the layoffs, saying they would be illegal during a shutdown.

The administration said in a Friday court filing that the unions' request should be denied because they lack the legal right to sue over federal personnel decisions.

A federal judge is due to hear the case on Oct 15.

Meanwhile, Trump said on Saturday that he has directed the Defense Department to use "all available funds" to ensure US troops are paid on Wednesday, a short-term fix that will not apply to the hundreds of thousands of federal workers who have been furloughed.

The directive removes one of the pressure points that could have forced Congress into action, now that the shutdown is likely to extend into a third week and possibly beyond.

Significant flight delays

Adding to the woes, travelers across the country are beginning to feel the impacts of the shutdown.

Airports across the United States have been experiencing significant flight delays recently because of a shortage of air traffic controllers, who have been required to work without pay since a government shutdown that began on Oct 1. Reports suggest employees have been calling in sick in increased numbers.

Over 52,000 flights were canceled ahead of the Columbus Day weekend.

The Federal Aviation Administration said on Friday that air traffic control staffing issues delayed travel for a fifth straight day.

The FAA said late on Friday it was experiencing staffing issues in Chicago, New York, Newark, San Diego, Dallas, Washington and Phoenix, among other airports. A temporary evacuation of the Atlanta air traffic control tower due to a fire alarm and reports of a strong natural gas odor also snarled flights.

Agencies via Xinhua