South Korea, China and Singapore are among the Asian countries facing a second coronavirus wave, spurred by people importing it from outside.

China, where the virus first emerged, confirmed it had no new domestic cases on Wednesday, for the first time since the outbreak began, a major milestone. But it reported 34 new cases among people recently returned to China.

Singapore also reported 47 new cases, of which 33 were imported - 30 of them returned Singapore residents.

South Korea saw a jump in new cases on Thursday with 152, though it is not clear how many were imported.

A new cluster there is centred on a nursing home in Daegu, where 74 patients have tested positive.

Experts say the sudden increase in cases has revealed the limits of both China’s sweeping lockdown of citizens and of the massive public testing and social distancing campaigns rolled out across Asia.

However, the number of imported coronavirus cases has jumped to 155 from fewer than 50 two weeks ago, according to Chinese government statistics. The National Immigration Administration said on Monday that about 120,000 people a day had entered China from abroad since the World Health Organization labelled the virus a pandemic on March 11. More than a dozen provinces, from Beijing to the border province of Yunnan, said international visitors, regardless of their condition and travel history, would be placed in quarantine for 14 days. Travelers will have to pay for food and accommodation during their quarantine.