The White House has dialled back US President Donald Trump’s claim that federal workers were already being fired amid the ongoing United States government shutdown.

The backtrack on Monday came as the government shutdown stretched into its sixth day, with Republicans and Democrats failing to reach a breakthrough to pass a budget that would fund an array of government agencies and services.

Democrats have taken a hard line in the negotiations, seeking to undo healthcare cuts in tax legislation recently passed by Republicans.

Both parties have blamed the other for the impasse, while the Trump administration has taken the atypical step of threatening to fire, not just furlough, some of the estimated 750,000 federal workers affected by the shutdown.

On Sunday, Trump appeared to suggest that those layoffs were “taking place right now”. He blamed Democrats for the firings.

But on Monday, White House Press Secretary Karoline Leavitt said that Trump was referring to the “hundreds of thousands of federal workers who have been furloughed”, not yet fired, amid the shutdown.

Still, she added, “the Office of Management and Budget is continuing to work with agencies on who, unfortunately, is going to have to be laid off if this shutdown continues”.

House Speaker blames Democrats, halts negotiations on funding

As salaries for hundreds of thousands of public sector employees were set to be withheld starting Friday, lawmakers indicated there had been little progress.

In the US Senate, another set of long-shot votes to fund the government were scheduled for late Monday.

Meanwhile, Republican House Speaker Mike Johnson told members of his party not to come to Congress unless the Democrats give way. He told reporters on Monday they should stop asking him about negotiations, saying it was up to the opposing party to “stop the madness”.

“There’s nothing for us to negotiate. The House has done its job,” Johnson said, referring to a funding bill passed by the chamber that has proved a non-starter in the Senate.

Democratic House Minority Leader Hakeem Jeffries, meanwhile, continued to portray Republicans as derelict.

“House Republicans think protecting the healthcare of everyday Americans is less important than their vacation,” he said. “We strongly disagree.”

With Republicans controlling the White House and holding slight majorities in both the House and the Senate, the funding bill is one of Democrats’ few points of leverage. In the Senate, Republicans hold 53 seats, but need 60 votes to pass the legislation.

They are using the position to push for the reversal of a tax law passed earlier this year that strips 11 million Americans of healthcare coverage, mainly through cuts to the Medicaid programme for low-income families, according to estimates from the nonpartisan Congressional Budget Office.

Democrats have said another four million US citizens will lose healthcare next year if Affordable Care Act health insurance subsidies are not extended, with another 24 million Americans seeing their premiums double.

Since the shutdown began on October 1, several services have been suspended as agency funding has run out. Others face a funding cliff. That includes the $8bn Special Supplemental Nutrition Programme for Women, Infants and Children (WIC), which could run out of funding to provide vouchers to buy infant formula and other essentials to low-income families within two weeks.

Federal workers deemed “essential” have remained on the job, but face working without pay until a resolution is reached. Military personnel could begin missing their paycheques after mid-October, advocacy groups have warned.

The agencies hit hardest by furloughs include the Environmental Protection Agency, the space agency NASA , and the Education, Commerce and Labor departments.

On Monday, US Transportation Secretary Sean Duffy said the government has seen “a slight tick up in sick calls” from air traffic controllers in certain areas since the shutdown began. That could lead to disruptions in air travel, he said.

“Then you’ll see delays that come from that,” he said. “If we have additional sick calls, we will reduce the flow consistent with a rate that’s safe for the American people.”

The US Transportation Department has also said that funds from a US government programme that subsidises commercial air service to rural airports were also set to expire as soon as Sunday.