MANILA—The World Health Organization (WHO) on Tuesday warned countries against relaxing quarantine restrictions before a strong health system is in place, saying this could trigger a resurgence of coronavirus disease (COVID-19) cases.

• WHO warns lifting of coronavirus lockdowns must be gradual

In the Philippines, the Luzon-wide lockdown is set to end on April 30 but President Rodrigo Duterte is yet to decide on an extension or gradual lifting, an option advised by the WHO to countries considering relaxing restrictions.

• To extend or not to extend Luzon lockdown? Duterte 'needs more time' to decide

“Lifting of lockdowns needs to be done gradually. I’m sure nobody wants to see another spike by lifting restrictions so soon,” Dr. Takeshi Kasai, WHO regional director for Western Pacific, said in an online press conference.

“If restrictions are relaxed before strong systems are in place to identify, isolate, and care for sick and tracing their contact, this will likely lead to a resurgence of disease.”

The virus has killed at least 170,000 worldwide with global infections at more than 2.4 million cases.

The 428 death toll and 6,459 confirmed cases in the Philippines are among the highest in Southeast Asia, with Singapore—once a model for its COVID-19 response—now battling a second wave of the coronavirus.

Like other countries, the Philippines is struggling to balance public health with the economy, which took a hit during the lockdown.

Low-risk businesses with systems in place to minimize the risk of infection may be considered for reopening should countries decide on a gradual lifting of restrictions, Kasai said.

“We have to be cautious. We really have to assess the situation,” Kasai said, noting “there’s no one-size, fits-all” approach to lifting restrictions.

“This COVID-19 battle is going to be a long one.”

Duterte’s spokesman said he would be “guided by science” on what to do next with the Luzon quarantine.