GENEVA —The coronavirus pandemic “continues to accelerate," with a doubling of cases over the last six weeks, the World Health Organization chief says.

WHO Director-General Tedros Adhanom Ghebreyesus says nearly 16 million cases have now been reported to the U.N. health agency, with more than 640,000 deaths worldwide.

Tedros will convene on Thursday WHO’s emergency committee, a procedural requirement six months after the agency’s declaration of a public health emergency of international concern, made on Jan. 30 for the coronavirus outbreak. The panel will advise him on the pandemic.

“COVID-19 has changed our world,” he told reporters from WHO’s Geneva headquarters on Monday. “It has brought people, communities and nations together — and driven them apart.”

He cited some factors that have proven effective in some countries, including political leadership, education, increased testing and hygiene and physical distancing measures.