Hong Kong will quarantine for 14 days all people entering the city starting midnight on Thursday to prevent an “explosion” of coronavirus cases around the world compromising one of the world’s most successful outbreak limitation campaigns.

Speaking at her weekly press briefing on Tuesday, the Chinese-ruled city’s leader Carrie Lam also advised residents to avoid all non-essential travel.

Hong Kong detected its first cases as early as January, but thanks to severe social distancing measures has managed to avoid the scale of contagion seen in other countries and territories. It now faced the risk that visitors carrying the virus could spread it in Hong Kong.