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, reported no new domestic cases on Thursday for the first time since it started recording numbers in January.
But it reported 34 new cases among people recently returned to China.
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.
On Wednesday, Singapore reported 47 new infections - of which 33 were imported, including 30 residents who had been infected abroad and brought the infection back.
All three countries had been showing success in controlling domestic cases, but there is concern that increases elsewhere could unravel their progress.