Image copyright Reuters Image caption At least 621 people on the ship are infected

Two Japanese passengers who contracted the new coronavirus on board a cruise ship quarantined in Japan have died, officials say.

Both were in their 80s with underlying health conditions. They were being treated in hospitals after being taken off the Diamond Princess last week.

At least 621 people on the ship tested positive for the virus, named Covid-19, the biggest cluster outside China.

Japan has defended its handling of the situation amid criticism.

The coronavirus, which originated in China's Hubei province last year, causes pneumonia-like symptoms.

Overall, there have now been 2,118 deaths and nearly 75,000 confirmed infections recorded in mainland China.

On Thursday, South Korea confirmed its first coronavirus death. Japan's neighbour also reported a sharp rise in virus cases, most of them from a newly identified cluster at a large religious community.

What is known about the two Japanese fatalities?

The victims were an 87-year-old man and an 84-year-old woman, Japan's health ministry said.

The man - from Kanagawa prefecture south of Tokyo - had had bronchial asthma and died from Covid-19.

The woman - from the capital - died from pneumonia believed to be caused by the coronavirus.

The victims have not been publicly named.

Image copyright Reuters Image caption Hundreds of passengers from the ship are making their way home

Japan's Health Minister Katsunobu Kato said they had been sent to medical facilities last week after showing symptoms.

"I believe they received the best possible treatment", he said.

What's the latest from the cruise ship?

The Diamond Princess was carrying 3,700 people in total and passengers who tested negative for the virus began leaving the ship on Wednesday after a 14-day quarantine.

Hundreds have now disembarked from the cruise liner docked in Yokohama. Others are set to leave over the next two days.

More than 150 Australian passengers have already arrived in Darwin, where they will begin two weeks of quarantine.

The first batch of people from Hong Kong have also flown back to the city, where they will similarly be quarantined.

UK Foreign Secretary Dominic Raab said Britons stranded on the ship would be able to board an evacuation flight home on Friday, as long as they were not showing symptoms of the virus.

Indonesia is also set to repatriate its citizens.

In other developments:

Chinese nationals were barred from entering Russia as of Thursday as a precautionary measure

Australia extended until 29 February its ban on international arrivals who have been to China

Why is Japan being criticised for its handling of the quarantine?

Japanese health expert Kentaro Iwata, professor at the infectious diseases division of Kobe University, visited the Diamond Princess and said the situation on board was "completely chaotic".

"The cruise ship was completely inadequate in terms of infection control," he said in a widely shared YouTube video which he has since taken offline.

Media playback is unsupported on your device Media caption Coronavirus expert: 'I was scared on board Diamond Princess'

US officials have also said moves to contain the virus "may not have been sufficient".

But on Thursday, Mr Kato responded to Mr Iwata's criticism, saying authorities had worked hard to deal with a very complicated situation.

"We've been doing our best in the circumstances," Mr Kato told Japanese lawmakers.

"Not only our officials at the health ministry but also Self-Defence Forces officials and medical officials are working desperately hard.

"We have specialists of infectious diseases [on the ship], and we get feedback from them about our operation every day, including dividing [the areas inside the ship]."

The health minister stressed that the cruise ship was "not a well-established place such as a hospital", and that the authorities "kept correcting" various problems on a daily basis.

"We have to examine and learn from this case because we think this is a global issue," Mr Kato said.

On Wednesday, Japan's National Institute of Infectious Diseases (NIID) released its report, which pointed to "clear evidence that substantial transmission of COVID-19 had been occurring prior to implementation of quarantine on Diamond Princess 5 February".

"The decline in the number of confirmed cases, based on reported onset dates, implies that the quarantine intervention was effective in reducing transmission among passengers," the report said.

What's the latest from China?

China has seen a sharp drop in the number of new infections.

There were 394 new confirmed cases and 114 deaths reported on Wednesday, down from 1,749 new cases on Tuesday, the National Health Commission said.

There are more than 1,000 cases outside of China, including on Diamond Princess and in Singapore, South Korea and Hong Kong.

Iran says two people infected with the virus have died in the city of Qom - the first reported deaths in the Middle East.

Image copyright AFP Image caption China says the virus mostly kills the sick and elderly

On Wednesday, Hong Kong said a 70-year-old man with underlying illnesses had become the territory's second fatality.

France, Japan, the Philippines and Taiwan have each had one death attributed to the virus.

Sharp rise in South Korea

South Korea on Thursday announced a jump of 31 confirmed Covid-19 infections - 23 of them from a newly identified cluster at a large religious community. South Korea now has a total of 82 confirmed cases.

The cluster is in the south-western city of Daegu - home to 2.5 million residents - and is believed to be linked to a 61-year-old woman who was confirmed to be infected earlier this week.

Image copyright Reuters Image caption Workers have sanitised the inside and surroundings of the Shincheonji Church branch

The Korean Centre for Disease Control said the woman had had contact with 166 people, who were asked to self-quarantine, South Korea's Yonhap news agency reports.

The religious sect known as the Temple of the Tabernacle of the Testimony, which has been accused of being a cult, said it had shut down its Daegu branch and that services in other regions would be held online or individually at home.

The mayor of the city has described the event as an "unprecedented crisis" and urged people in the city to stay indoors.