The WHO leader said it was premature to rule out a potential link between the pandemic and a lab leak.

BERLIN — The head of the World Health Organization acknowledged it was premature to rule out a potential link between the COVID-19 pandemic and a laboratory leak, and he said Thursday he is asking China to be more transparent as scientists search for the origins of the coronavirus.

In a rare departure from his usual deference to powerful member countries, WHO Director-general Tedros Adhanom Ghebreyesus said getting access to raw data had been a challenge for the international team that traveled to China this year to investigate the source of COVID-19. The first human cases were identified in the Chinese city of Wuhan.

Tedros said that the U.N. health agency based in Geneva is asking “China to be transparent, open and cooperate, especially on the information, raw data that we asked for at the early days of the pandemic.”

He said there had been a “premature push” to rule out the theory that the virus might have escaped from a Chinese government lab in Wuhan, undermining WHO’S own March report, which concluded that a laboratory leak was “extremely unlikely.”

“I was a lab technician myself, I’m an immunologist, and I have worked in the lab, and lab accidents happen,” Tedros said. “It’s common.”

In recent months, the idea that the pandemic started somehow in a laboratory — and perhaps involved an engineered virus — has gained traction, especially with President Joe Biden ordering a review of U.S. intelligence to assess the possibility in May.

China has argued that attempts to link the origins of COVID-19 to a lab are politically motivated and has suggested that the outbreak might have started abroad.

At WHO’S annual meeting of health ministers in the spring, China said that the search for COVID-19’S origins should continue — in other countries. In other developments:

■ Coronavirus cases in Tokyo have surged above 1,300 for a six-month high, just one week before the Olympics. There are concerns a dramatic increase could flood hospitals during the Olympics, which start on July 23.

■ A top official at the European Medicines Agency says a decision on whether to recommend that Moderna’s COVID-19 vaccine be authorized for children is expected late next week.

■ Some French restaurant staff are concerned that new mandatory COVID-19 passes will turn them into coronavirus police instead of purveyors of culinary pleasures. Starting next month, all diners in France must show a pass proving they’re fully vaccinated, or recently tested negative or recovered from the virus.