China, where the coronavirus outbreak first erupted in December, logged fewer new infections on Thursday, but measures restricting movement across the country have tightened in some places due to fear of imported cases.
China had 35 new cases of the disease on April 1, all of which were imported, the National Health Commission said on Thursday.
Meanwhile, the central province of Hunan, which had recently downgraded its emergency response to the lowest level, reported its first imported infection on Wednesday, state media reported on Thursday, citing the provincial health commission.
Chinese authorities remain concerned about the risks posed by imported cases of COVID-19, and have in recent days banned foreign passport holders from entering and ordered a sharp reduction in the number of international flights.
China currently allows no more than 134 international flights per week to enter the country to meet demand from citizens and students abroad wishing to return home, and just 108 flights have been granted permission this week, Lu Erxue, the deputy director-general of China's civil aviation administration said at a briefing on Thursday.
A total of 1.6 million Chinese students study overseas, including 410,000 in the United States, 230,000 in Canada and about 220,000 in the United Kingdom, Ma Zhaoxu, China's vice-minister of foreign affairs, said at the same briefing.
Of those, 1.42 million are still abroad. Chinese consulates have reported a total of 36 overseas Chinese students with confirmed cases of COVID-19, he said.
"For countries where the epidemic is severe, where there are students who truly are in difficulty and urgently need to return, the Party and government will take the necessary measures to assist them in a step-by-step, orderly fashion," Ma said.
China's civil aviation administration arranged a total of nine flights between March 4 and 26 to bring Chinese citizens back from overseas, and dispatched another plane on Thursday to ferry about 180 students back to China from the UK, Ma said.
China has also seen a gradual reintroduction of restrictions, including closures of cinemas that had been permitted to reopen, amid worries that early relaxation of lockdowns could spark a second wave of infections.
On Wednesday, a county in the central province of Henan said it had banned people from leaving without proper authorisation, and prevented residents from leaving their homes for work without clearance following several cases of coronavirus infection in the area.
The number of new asymptomatic cases fell sharply to 55 on April 1, from 130 the day before.
Users of Chinese social media have expressed fear that carriers with no symptoms could be spreading the virus unknowingly, especially as authorities ease curbs on travel for previous hotspots now that infections have subsided.
Last week, WHO epidemiologist Maria van Kerkhove said symptomatic patients were the main drivers of transmission, while most of those classified as asymptomatic developed symptoms a few days after diagnosis.