The US Supreme Court on Thursday blocked President Joe Biden's mandate obligating employees at all businesses with 100 workers or more to get vaccinated against the coronavirus or submit to weekly Covid testing and show negative results if they want to remain on the job.

The presidential order would have gone into force in February.

The high court gave the green light, however, to another Biden mandate for workers at more than 50,000 health facilities around the country to get vaccinated against Covid. Some of those health facilities receive federal subsidies for Medicare and Medicaid and the move affects some 17 million people.

Six justices, all of them with the court's conservative majority, signed on to the reversal of Biden's order for people at firms with 100 or more workers to get vaccinated, while the three progressive justices issued a dissenting opinion on the ruling.