The requirement to wear face masks has come to an end in Spain and the United States, via a government announcement and a judicial ruling respectively, as five countries prepare to co-host the second Global COVID-19 Summit next month.

Spain will largely abolish the requirement that people wear protective masks as of Wednesday as the number of coronavirus cases continues to fall.

A corresponding decree was approved by the cabinet in Madrid on Tuesday.

After almost two years, people will no longer have to wear masks in almost all enclosed public spaces.

Masks, however, remain compulsory in hospitals and on public transport as well as in health centres and homes for senior citizens.

The danger posed by the coronavirus has "clearly decreased," Health Minister Carolina Darias told journalists after the cabinet meeting.

Meanwhile, the White House said US President Joe Biden's administration may appeal a court ruling blocking the US mask mandate on public transport.

A federal judge in Florida on Monday ruled that the 14-month-old directive was unlawful, overturning a key presidential effort to reduce the spread of COVID-19.

"We're continuing to encourage people to wear masks," White House press secretary Jen Psaki told reporters on Air Force One, pending a decision by the Justice Department on whether it will appeal Monday's ruling.

After landing in Portsmouth, New Hampshire, a short while later, Biden, asked whether people should continue to wear masks on planes, said, "It's up to them".

A US administration official said on Monday that while government agencies were assessing potential next steps, the court's decision meant the CDC's public transportation masking order was no longer in effect.

Psaki said on Tuesday that the Justice Department would take a couple of days to decide whether to appeal the court ruling, which came in a lawsuit filed last year in Tampa, Florida.

The ruling was greeted by many travellers across the US.

A pilot declared over the loudspeaker on a cross-country Delta Air Lines flight that passengers were no longer required to wear masks, eliciting cheers from the cabin and prompting some on board to immediately toss their face coverings onto their seats.

"Feel free to burn them at will," a train conductor told New Jersey commuters.

Other passengers were confused, startled and angered by the abrupt change, however, especially those who booked trips in the belief that their unvaccinated children would be travelling in a masked environment.

On a Southwest Airlines flight on Monday from Detroit to Nashville, the change to optional status was incorporated into the safety announcements, prompting murmurs and fist pumps from some passengers and no audible complaints.

The US, Belize, Germany, Indonesia and Senegal will co-host the second Global COVID-19 Summit, to be held virtually on May 12.

The summit will redouble the international community's collective efforts to end the acute phase of the pandemic and prepare for future health threats.

This summit follows the first Global COVID-19 Summit convened by the US in September last year.

In advance of the May 12 Summit, the co-host countries have urged world leaders, members of civil society, non-governmental organisations, philanthropists, and the private sector to make new commitments and bring solutions to vaccinate the world, save lives and build better health security.

with reporting from AP and Reuters