- Coronavirus pandemic
Image source, Getty ImagesImage caption, The mandate would apply to tens of millions of US workers
A US appeals court has temporarily blocked President Joe Biden's plans for a vaccine mandate for businesses.
The law would require workers at private companies with more than 100 employees to get fully vaccinated against Covid-19 or be tested weekly.
But the court found "grave statutory and constitutional" issues with the rule, set to be introduced in January.
It said it was suspending the mandate and gave the Biden administration until Monday to respond.
Five Republican-led states – Texas, Louisiana, Mississippi, South Carolina and Utah – as well as private companies and religious groups, had filed legal challenges against the mandate.
They accused the president of overstepping his authority.
Louisiana's Attorney General Jeff Landry tweeted that the court's decision was a "major win for the liberty of job creators and their employees".
- The US workers refusing to get jabbed
If enforced, the ruling by the the fifth US circuit court of appeals would be a blow to the Biden administration's sweeping measures to extend vaccination.
Mr Biden says the mandate, which would cover more than two-thirds of the nation's workers, would set a national standard of safety at work.
On Thursday, the president said employees at large companies would have to be fully vaccinated by 4 January, calling vaccination "the single best pathway out of this pandemic".
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Many businesses in the US already require their employees to be vaccinated. There are also requirements for military and federal contractors.
But opponents say it is not constitutional for a president to impose such a sweeping nationwide rule.
Republican Texas Governor Greg Abbott, who has opposed government mandates on vaccines and masks, applauded the court's decision.
"We will have our day in court to strike down Biden's unconstitutional abuse of authority," he said.
But Labor Department solicitor Seema Nanda said it was "confident in its legal authority" to issue the rule.
"We are fully prepared to defend this standard in court," she said.