The death toll from China's coronavirus outbreak soared to 722 on Saturday as Hong Kong imposed a mandatory quarantine on mainland arrivals to block the spread of an epidemic that has caused global panic.

With 86 more people dying in mainland China -- the highest one-day jump so far -- the toll was closing in on the 774 killed worldwide during the 2002-2003 SARS epidemic.

Nearly 35,000 people have been infected by the new strain, which is believed to have emerged in a market selling wild animals in the central city of Wuhan last year before spreading across China