Japan's capital will seek to extend until May 31 its state of emergency aimed at curbing coronavirus infections, Governor Yuriko Koike has said, a move that could spark more questions about its ability to host the Olympics.

Japan had hoped a “short and powerful” emergency would contain a fourth wave of infections just under three months before Tokyo is set to host the Olympic Games from July 23.

“Based on the analyses from various angles, my thinking is that we need an extension of the state of emergency,” Koike said.