THESSALONIKI, Greece – A Greek prosecutor has ordered an investigation into a string of infections at a retirement home in northern Greece, where 33 of the 150 residents and three staff members have tested positive for COVID-19.

Authorities say 20 people from the home at Asvestochori, a village outside the northern city of Thessaloniki, were taken to a hospital Wednesday with mild symptoms. The disease is believed to have been spread by a staff member who caught it from a relative who had visited a popular holiday resort.

The investigation was ordered Thursday.

Greece has seen a major rise in COVID-19 infections, which reached 262 on Wednesday -- the highest since the virus outbreak.

The country of 11 million has registered about 6,200 confirmed cases, and 216 deaths.

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HERE’S WHAT YOU NEED TO KNOW ABOUT THE VIRUS OUTBREAK:

— Virus exposes economic, racial divide in French health care

— ‘Impossible’: School boards are at heart of reopening debate

— Experts warn Spain is losing the 2nd round in virus fight

— Like many countries, Rwanda is finding it impossible to test each of its citizens for the coronavirus amid shortages of supplies. But researchers there have created an approach that’s drawing attention beyond the African continent.

— German authorities worked through the night to clear a backlog of coronavirus tests from travelers after it emerged 900 people who were positive for COVID-19 had yet to be informed.

— A puzzling new outbreak of the coronavirus in New Zealand’s largest city has grown to 17 cases, with officials saying the number will likely increase further. And a lockdown in Auckland designed to extinguish the outbreak could be extended well beyond an initial three days.

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— Follow AP’s pandemic coverage at http://apnews.com/VirusOutbreak and https://apnews.com/UnderstandingtheOutbreak

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HERE’S WHAT ELSE IS HAPPENING:

THIMPU, Bhutan — The Himalayan kingdom of Bhutan has imposed its first nationwide lockdown due to a virus infection in a returning traveler who had been released from quarantine.

The government issued a stay-at-home order for its approximately 750,000 people, and all schools, offices and commercial establishments were closed.

The government’s statement said the lockdown would be enforced from five to 21 days “to identify and isolate all positive cases, immediately breaking the chain of transmission.”

The 27-year-old Bhutanese woman returning from Kuwait tested negative in mandatory quarantine for arriving travelers. But between her discharge from quarantine and her positive test result Monday, she is believed to have traveled extensively in Bhutan.

The tourism-dependent country closed its borders to foreign travelers in March after an American tourist was hospitalized with COVID-19. Bhutan’s 113 reported infections were all quarantined travelers, except for one with conflicting test results.

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MELBOURNE, Australia — The coronavirus outbreak centered in Australia’s second-largest city showed a decline in new infections Thursday, though the state’s leader urged continued vigilance.

Victoria state Premier Daniel Andrews said there were 278 new infections and eight new deaths, down from around 700 daily at the peak of the outbreak.

Daniels said the lower numbers indicate the lockdown restrictions in Melbourne are working but urged people to stay the course.

“We would just caution against any Victorian thinking that we aren’t in the midst of a real marathon,” Daniels said. “This is an endurance race, and we need to stay the course on this. We need to be as vigilant each and every day.”

Meanwhile, neighboring New South Wales state, which includes Australia’s largest city Sydney, recorded 12 new cases and one death.

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SEATTLE — The Seattle school board has voted unanimously to begin the academic year with remote teaching only.

The Seattle Times reports the state’s largest school district approved the plan Wednesday.

The remote learning plan passed with a wide-ranging amendment from school board members that directs the superintendent to explore creating outdoor classes. It also reinforces teaching of Black studies and curricula developed by Indigenous communities.

But the district’s plans are far from set because it is still bargaining with the teachers union. Those discussions will set the parameters for how teachers spend their time and for the support the district will provide in an online learning environment.

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BEIJING — New locally transmitted cases of the coronavirus reported in China have fallen into the single digits, but Hong Kong is seeing another rise in hospitalizations and deaths.

China’s National Health Commission said Thursday that eight new cases were registered in the last 24 hours in the northwestern region of Xinjiang, whose main city of Urumqi has enacted lockdown measures and travel restrictions. An additional 11 cases were brought by Chinese returning from overseas.

Hong Kong, meanwhile, has 62 new cases, up from 33 on Wednesday, along with an additional five deaths.

The semi-autonomous southern Chinese city has required masks be worn in all public settings and limited indoor dining among other measures to curb a new outbreak.

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SEOUL, South Korea — South Korea has reported 56 new cases of the coronavirus as clusters continue to pop up in cities.

The figures announced by South Korea’s Centers for Disease Control and Prevention on Thursday brought the caseload to 14,770 infections, including 305 deaths. Forty-three of the new cases were from the Seoul area and two were from Busan, the country’s second-largest city, where infections have been reported at schools and among foreign cargo ship workers.

South Korean authorities have employed an aggressive test-and-quarantine campaign against COVID-19, using mobile-phone location data and credit-card records to trace contacts and smartphone tracking apps to monitor tens of thousands quarantined at home.

Visitors at nightclubs, baseball stadiums and other facilities deemed as “high-risk” must register with smartphone QR codes so they can be easily located when needed.

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UNITED NATIONS — U.N. Secretary-General Antonio Guterres says the cordonavirus pandemic not only threatens gains in fighting poverty and building peace but risks exacerbating existing conflicts and generating new ones.

The U.N. chief told a Security Council meeting Wednesday that his March 23 call for an immediate cease-fire in conflicts to tackle the virus led a number of warring parties to deescalate or stop fighting. But, he added, “regrettably, in many instances, the pandemic did not move the parties to suspend hostilities or agree to a permanent ceasefire.”

Guterres predecessor as secretary-general, Ban Ki-moon, told the council it is astonishing that the world has locked down billions of people, closed borders and suspended trade, but has failed to put conflicts on hold.