Japan’s Prime Minister Shinzo Abe on Thursday urged schools nationwide to close for several weeks to prevent the spread of the new coronavirus, as authorities reported the country’s fourth death linked to the outbreak.

The move comes as crew members from the Diamond Princess, a coronavirus-stricken cruise ship quarantined off Japan, began leaving the vessel where more than 700 people have tested positive for the disease.

Many public elementary schools and junior high schools in northern Hokkaido, where the death of a man in his 80s infected with the virus was confirmed on Thursday, were already closed after a cluster of infections prompted the governor to request public schools close for about a week.The city of Osaka also said it will close its kindergartens, elementary and junior high schools from Saturday for two weeks.

Abe’s call comes after the government urged organisers of major events to consider cancelling them, and called on businesses to allow employees to work from home or commute off-peak.Authorities have said the coming two to three weeks will be critical in determining whether they can stem the outbreak of the virus, which has infected nearly 200 people in the country.

“It’s extremely important to prevent one patient cluster from creating another and we think we should take thorough measures,” Abe said at a cabinet-level meeting on the virus.He also urged ministers to work on legislation to minimise the negative impact on the economy and the daily lives of Japanese.

Japanese authorities have progressively stepped up their response to the outbreak, but faced criticism for acting slowly and for their handling of the Diamond Princess, where more than 700 people contracted the virus.

Most passengers have now left the boat, including nearly 1,000 who were allowed to leave after testing negative. But several have since tested positive for the virus, and the health ministry admitted others were not tested during the quarantine period.

Those leaving the boat will be placed in medical observation for 14 days at government-designated dormitories before being allowed to leave Japan, they said.