MIAMI, June 10 (AFP) - Two guests on one of the first cruise ships to sail from North America since the COVID-19 pandemic hit tested positive on Thursday (Jun 10), the cruise company said, adding that all passengers and crew had been vaccinated.

Cruise operator Royal Caribbean and the Celebrity Millennium, carrying about 600 passengers and 650 crew, set sail from the Caribbean island of Saint Maarten on Saturday for a seven-day cruise including stops in Barbados, Aruba and Curacao.

"Two guests sharing a stateroom onboard Celebrity Millennium tested positive for COVID-19 while conducting the required end-of-cruise testing," Royal Caribbean said in a statement.

"The individuals are asymptomatic and currently in isolation."

It said that the ship exceeded US COVID-19 guidelines, and all guests were required to show proof of vaccination as well as a negative COVID-19 test before sailing.

The US Centers for Disease Control and Prevention (CDC) currently requires that more than 95 per cent of passengers and crew be vaccinated in order for cruise lines to bypass a requirement for trial voyages.

Cruise operations were suspended on Mar 14 last year when the CDC issued a "no sail order" to prevent the further spread of the coronavirus. Several ships already had deadly outbreaks on board.