Singapore, Jan. 24 -- China has taken the unprecedented move of locking down cities at the heart of a new Sars-like outbreak that has spread swiftly across provinces and the world, killing at least 17 and infecting more than 630.

In a dramatic effort to curb the sweep of the mutating virus, officials in Wuhan announced at midnight on Wednesday that the city, where the mystery coronavirus originated last month in a wet market that sold live animals, was being sealed off.

Last night, the authorities in the surrounding cities of Huanggang, Ezhou, Chibi and Xiantao in the same Hubei province in central China also imposed travel restrictions. The toughest measures were taken in Huanggang, where the train station was shut, roads closed and bu...