China locked down two cities at the centre of the deadly coronavirus outbreak on Thursday, banning planes and trains from leaving in a move aimed at containing the disease which has already spread to other countries.

The respiratory virus has claimed 17 lives since emerging from a seafood and animal market in Wuhan. It has infected hundreds of other people nationwide and has been detected as far away as the United States.

In Beijing, the government cancelled massive gatherings which usually attract masses of people at temples during the New Year holiday.

More than 570 people have been infected with the virus across China — with most cases found in Wuhan, where a seafood market that illegally sold wild animals has been identified as the centre of the outbreak.

The coronavirus has caused alarm because of its similarity to SARS (Severe Acute Respiratory Syndrome), which killed nearly 650 people across mainland China and Hong Kong in 2002-2003. Like SARS, it can be passed among people through the respiratory tract.

The World Health Organization on Wednesday delayed a decision on whether to declare a global health emergency. The emergency committee will meet again on Thursday.