Facing a worried nation on the brink of a potential dramatic spike in novel coronavirus patients, Prime Minister Shinzo Abe on Tuesday pleaded with residents to stay home to protect their lives to counter what he called “the biggest crisis since World War II.”

Abe's news conference followed the official declaration of a state of emergency earlier in the day. The declaration, which became effective the same day and will continue until at least May 6, the end of the Golden Week holiday, covers Tokyo and Osaka, as well as Saitama, Kanagawa, Chiba, Hyogo and Fukuoka prefectures.

Noting that the country’s health care system is increasingly strained, Abe asked people to change their behavior by cutting back interactions with others by between 70 and 80 percent for a month. If the rate of infection remains the same in Tokyo, Abe warned that the number of patients could balloon to 10,000 in two weeks and 80,000 in one month.