Pedestrians wear face masks amid concerns over the spread of the COVID-19 novel coronavirus, in Tokyo on Tuesday. In Japan, the confirmed number has topped 861, including passengers previously quarantined at the Diamond Princess cruise ship. Photo: AFP

 Japan's Prime Minister Shinzo Abe has declared a state of emergency over the coronavirus outbreak, the first of its kind in the country.

The state of emergency, starting Wednesday, will be effective until May 6 and cover seven prefectures including Tokyo, Osaka and Fukuoka.

With the declaration, prefectural governors will be able to tell the public to stay at home and request the closure of schools and other facilities.

So far, 4,100 infections have been reported in the country, with 97 deaths.