Governments in Asia are preparing measures to head off a new wave of coronavirus cases as people flee an explosion of the disease in Europe, North America and the Middle East.
As the world mobilises to battle the virus, China, Hong Kong, Singapore and Taiwan have been relatively successful in curbing the spread so far.
But a surge in imported cases in recent days has raised alarm that those efforts could rapidly unravel.
"In many countries the number of confirmed cases can be described as explosive," Hong Kong leader Carrie Lam told a press briefing on Tuesday.
"If we don't adopt some strict measures...I'm afraid all precaution efforts done in the past two months would be wasted."
The latest tally from mainland China, the original epicentre of the coronavirus, showed 21 new confirmed cases on Monday, of which 20 involved infected travellers arriving from abroad, mostly Chinese nationals. Hong Kong said most of the recent confirmed cases in the past two weeks were imported.
In Taiwan, 24 new cases up to Tuesday were all imported, while South Korea had 44 new infections involving infected travellers as of Sunday.
Singapore confirmed 17 new infections on Monday, its biggest daily jump in cases, with 11 of those imported.
The rush to flee virus hotspots in Europe and the United States has pushed up the price of flights. A ticket from London to Hong Kong was going for up to HK$50,000 on Monday night as people tried to get to the city before it imposed tougher restrictions.
"It is safer home than in Britain as the policy to contain the outbreak under Boris Johnson is doubtful," said Ling, a Cambridge University student after landing in Hong Kong wearing a surgical mask and rubber gloves.
The number of confirmed coronavirus cases in Britain rose to 1,543, up from 1,372 the day before, the health ministry said on Monday. The British death toll rose to 55.
Four of Hong Kong's 157 confirmed coronavirus patients have died, while more than 3,200 people have died from the disease in mainland China, the highest number of fatalities.
Measures in China, Hong Kong and Singapore, include city-wide lockdowns, border tightening, contact tracing efforts and strict social distancing.
The virus has already taken a heavy economic toll, especially in mainland China and global financial hub Hong Kong, so any rise in new cases could be devastating.
Hong Kong on Tuesday toughened measures on travellers, requiring 14 days of quarantine for those entering the city as of midnight on Thursday, and joined Singapore in advising against all non-essential travel.
China said all inbound, non-transit travellers to Beijing need to be isolated for 14 days at designated quarantine venues, mostly hotels in the city.