Singapore will shut most schools from Wednesday after the city-state reported the highest number of local COVID-19 infections in months, including several that were unlinked.
All primary, secondary and junior colleges will shift to full home-based learning from Wednesday until the end of the school term on May 28.
"Some of these (virus) mutations are much more virulent, and they seem to attack the younger children," said Education Minister Chan Chun Sing.
On Sunday, Singapore confirmed 38 locally transmitted COVID-19 cases, the highest daily number since mid-September, of which 18 are currently unlinked.
Singapore has reported more than 61,000 virus cases, with the bulk linked to outbreaks last year in foreign worker dormitories, and 31 deaths.
Sunday's new cases were the highest number of local infections outside of the dormitories in a year.
"The sharp rise in the number of community cases today requires us to significantly reduce our movements and interactions in the coming days," Chan added.
The Asian trade and financial hub of 5.7 million people had until recently been reporting almost zero or single-digit daily infections locally for months.
Though Singapore's daily cases are still only a fraction of the numbers being reported among its Southeast Asian neighbours, infections have been increasing in recent weeks.
From Sunday, the government implemented its strictest curbs on gatherings and public activities since a lockdown last year.
Over a fifth of the country's population has completed the two-dose vaccination regimen with vaccines from Pfizer-BioNTech and Moderna.
Authorities will invite people under 45 years of age to receive shots from the second half of May.
The speed of Singapore's inoculation programme is being limited by the pace of vaccine supply arrivals.
Experts are studying whether to give one dose of the vaccine and extend the interval between shots, said Health Minister Ong Ye Kung.
The government is also working on plans to vaccinate children below 16 years once regulatory approval is granted.
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