Photo/Illutration Tokyo Governor Yuriko Koike at a news conference on March 25 (The Asahi Shimbun)

Tokyo Governor Yuriko Koike on Wednesday warned of an "overshoot" of coronavirus infections and urged residents to stay indoors at the weekend as much as possible.

Koike made the statements at a news conference where she warned of a "severe" situation after more than 40 new infections were announced in the capital. It was its biggest one-day increase.

The city has become the center of Japan's coronavirus epidemic, with 211 cases, more than any other region after increases this week.

It overtook the hard-hit northern island of Hokkaido island on Tuesday as the prefecture with the most infections, public broadcaster NHK reported.

The outbreak has infected 1,271 people in Japan as of Wednesday evening, with 44 deaths linked to the virus, NHK said. That excludes 712 cases and 10 deaths from a cruise ship moored near Tokyo last month.

The International Olympic Committee and Japanese government on Tuesday agreed to put back the Tokyo 2020 Olympics to 2021 over the outbreak.

Tokyo's new infections came after Koike warned that a lockdown of the capital was possible if it saw an explosive rise in cases.

Koike on Monday called on residents to exercise restraint to avoid a lockdown. She said the next three weeks were critical for whether Tokyo would see an "overshoot"--an explosive rise--in virus cases.

Japan's northern prefecture of Hokkaido ended a state of emergency over its outbreak of the coronavirus, which has seen 167 cases.

The outbreak has now infected more than 420,000 across 196 countries, according to a Reuters tally, with almost 19,000 deaths linked to the virus.