Tokyo Governor Yuriko Koike has issued a warning in the city for a possible resurgence of the coronavirus.
Tuesday's notice comes after 34 new cases were reported, the highest total in a month, and coming just days after the city lifted its state of emergency.
Only a handful of new cases were reported at the end of May.
Koike said she is not ready to reimpose an official citywide alert but said if the number rises to at least 50 new cases a day, she will again order businesses to shut down.
The governor said she suspects the return of Japanese nightlife, such as karaoke bars, has brought on the new infections.
Health experts around the world have been warning of a spike in new cases if governments and businesses reopen too soon.
South African officials say the number of cases there has doubled every two weeks and now stands at more than 35,000.
A pupil at the City Kidz Pre & Primary School in the Inner City district in Johannesburg has his temperature measured as he enters the school premises, in South Africa, June 1, 2020.
Some businesses in Bolivia, Mexico, and Venezuela started reopening this week even after the WHO declared Latin America and the Caribbean the world's coronavirus epicenter.
"Clearly the situation in many South American countries is far from stable. There is a rapid increase in cases and those systems are coming under increasing pressure," WHO emergencies director Dr. Mike Ryan said Tuesday.
The experts also warn of a possible resurgence in the United States, where thousands of people have been protesting in the streets against racial violence, ignoring the social distancing warnings and urgings to wear masks.
Report on minorities and COVID
A new British report Tuesday say minorities in England have died of COVID-19 at rates higher than whites.
The Public Health England report says ethnic Bangladeshis are at risk of death at a rate twice as high as white Britons. Britons of other Asian backgrounds, including Chinese, Indian, and Pakistani, and black Caribbean ethnicities have a 10% to 50% greater chance of dying from COVID-19.
The report did not give any recommendations on how to reduce those numbers.
British Health Secretary Matt Hancock said it cannot be disputed that blacks and other minorities are at greater risk of death, but also expressed some dismay at the lack of guidance at this time.
"This is a particularly timely publication because right across the world people are angry about racial injustice. I totally understand the urgency, the importance and the sensitivity of getting this right," Hancock said, referring to the uproar over the death of George Floyd in the U.S.
"I get that. Black lives matter," he said.