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.

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.