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South Korea on Thursday reported the first local case of human-to-human transmission of the deadly virus that has killed 170 people in China and spread to more than a dozen countries.

The announcement comes as international airlines are either suspending or paring back services in and out of China in a bid to halt the virus reaching further.

The Centers for Disease Control and Prevention Korea confirmed two more cases Thursday, bringing the total six.

The sixth confirmed patient, a 56-year-old South Korean man, was diagnosed after being "in contact with the third patient" in the South, it said.

He was quarantined at a hospital in Seoul.

The other five patients were diagnosed after arrival from the Chinese city of Wuhan, where the virus is believed to have emerged from an animal and .

Apart from China, human-to-human transmission has also been reported in Japan, Germany and Thailand.