South Africa is holding more than 1,700 people on a cruise liner and a cargo vessel off the coast of Cape Town because of coronavirus.
A crew member of cargo ship MV Corona is suspected to have the virus.
He had been on a flight with six other people, who then boarded Italian-flagged cruise liner MV Aidamira.
South Africa has 116 cases of coronavirus and President Cyril Ramaphosa has declared a state of disaster, restricting travel.
Nearly half - 35 out of 72 - of South Africa's land border crossings were closed on Monday, along with two of its eight sea ports.