China has imposed quarantine measures on a major city at the center of a virus outbreak, banning trains and planes from leaving it in an attempt to curb the contagious disease that has so far claimed the lives of 17 people.

On Thursday, authorities in Wuhan, the capital city of China�s central province of Hubei, also suspended public buses and subways, insisting that the inhabitants of the city - 11 million people - not leave without a special reason.

The special anti-virus command center of Wuhan said on Thursday that the quarantine measures, which came into effect at 0200 GMT, were meant to effectively cut off the virus spread, resolutely curb the outbreak and guarantee the people�s health and safety.

The coronavirus, known technically as the 2019 Novel Coronavirus (2019-nCoV), can be passed among people through the respiratory tract. It originated in a seafood market in Wuhan that illegally sold wild animals in the major transport hub late last year.

The mysterious virus, which has now infected more than 570 people in 13 Chinese provinces and municipalities, including in Beijing and Shanghai, has already spread to some other countries, including Japan, South Korea, Thailand, and the United States.

Authorities in the besieged city have also made it mandatory to wear a mask in public places.

Those who disregard the warning will be punished according to relevant laws and regulations, the official Xinhua news agency cited Wuhan�s government as warning.

The disease has caused alarm in China and beyond since it shows close similarity to SARS (Severe Acute Respiratory Syndrome), a contagious and sometimes fatal respiratory illness that claimed the lives of some 650 people across mainland China and Hong Kong in 2002 and 2003.

Wuhan�s tourism and culture department has already cancelled all group tours until February 8, also according to Xinhua.

The lockdown on Wuhan comes just ahead of the Chinese New Year on Friday, and hundreds of millions of people have been traveling in packed trains, planes, and buses across the country.

On Wednesday, the World Health Organization (WHO) failed to reach an internal agreement on whether to declare a global health emergency, a rare instrument used only for the worst outbreaks.

The UN agency said that its emergency committee would meet again on Thursday, after its chairperson, Didier Houssin, said experts had been divided on whether the novel coronavirus outbreak in China constituted a Public Health Emergency of International Concern (PHEIC).

Asked about Wuhan�s transport shutdown, WHO chief Tedros Adhanom Ghebreyesus said, By having a strong action, not only will they control the outbreak in their country but they will also minimize the chances of this outbreak spreading internationally.

Ghebreyesus said he needed more information but he hailed the very, very strong measures already taken to control the outbreak.

Chinese health officials say that animals are suspected to be the primary source of the outbreak, speculating that the coronavirus can mutate.