Of the 56 new community infections, 41 were linked to the KTV outbreak, the health ministry said.

The ministry earlier this week said it was investigating infections among Vietnamese hostesses who frequented KTV lounges or clubs and was offering free Covid-19 testing to anyone potentially exposed.

The first known case was a Vietnamese woman who sought medical help on Sunday, local media reported.

Singapore has yet to reopen KTV lounges and clubs and authorities said the places where the virus spread were operating as food and beverage outlets.

Health Minister Ong Ye Kung said police would take action against violators.

“Any outlets providing hostess services, dice games and all this very close contact, were never allowed,” he told local media, according to CNA.

“So for this to now happen has been troubling (and) disappointing.”

Ong said there was no plan to reverse recently loosened restrictions because of the cluster, citing progress in vaccinations.

Among those infected was also a cruise passenger hospitalised today. Nearly 3,000 passengers and crew were confined to their cruise cabins, awaiting Covid-19 tests.

Singapore has dealt swiftly with most of its coronavirus outbreaks and imposed targeted restrictions in May aimed at slowing the spread of the Delta variant.

It is aiming to complete the vaccination of two-third of its population by Aug 9.