YOKOHAMA, Feb. 20 (CNA) - Two passengers from a coronavirus-hit cruise ship moored near Tokyo have died, Japanese media reports said on Thursday (Feb 20), as a second group of passengers began disembarking after two weeks quarantined on board.

A man and a woman in their 80s who had been infected have died, public broadcaster NHK said, citing government sources.

Both had underlying conditions and had been taken off the ship on Feb 11 and Feb 12 before being treated in hospital, NHK added.

More than 620 of the passengers on the Diamond Princess liner have been infected on the ship, which has been quarantined since Feb 3, initially with about 3,700 people on board.

The rapid spread of the disease - Japan has well over half of the known cases outside China - has sparked criticism of authorities just months before Tokyo is due to host the Summer Olympics.

Health Minister Katsunobu Kato on Thursday defended Japan's response in parliament, telling lawmakers that officials have taken expert advice and responded to issues on a daily basis.

In a move to reassure the public, the health ministry also issued a statement in both English and Japanese that said all passengers had been required to stay in their cabins since Feb 5 to contain the virus.

The disease has now claimed more than 2,000 lives in China and spread panic worldwide.

Hundreds more cases have been reported in two dozen countries, including in Iran, which reported its first two cases of the virus - both fatal. Those were the first deaths in the Middle East.