SINGAPORE - There were 28 new Covid-19 cases, including 21 in the community, as at noon on Monday (May 17), said the Ministry of Health (MOH).

Of the community cases, 11 are currently unlinked. The remaining 10 are linked to previous cases.

Of the new community patients, six had already been placed on quarantine.

There were also seven imported cases who had been placed on stay-home notice on arrival in Singapore, said the ministry.

Of these, two are returning Singaporeans or permanent residents.

There were no new cases in the workers' dormitories.

The new cases take Singapore's total to 61,613. More details will be announced on Monday night.

In a statement on Monday, Marina Bay Sands (MBS) announced that its casino will be closed temporarily for deep cleaning from noon after two casino staff were confirmed to have the virus on Sunday.

"Their last day at work was on the morning of May 15," said MBS. It was also working with MOH to trace guests who may have interacted with the employees.

On Sunday, 38 new community infections were announced by the ministry, with 21 cases linked to previous patients.

Nine more people, including four primary school pupils, who tested positive for Covid-19 have been linked to the Learning Point tuition centre cluster.

They comprise pupils from Kong Hwa School, Yu Neng Primary School and St Margaret's Primary School.

This took the total number of cases in the cluster to 18, after a 50-year-old woman who works as a tutor there was confirmed to have Covid-19 on May 12.

Two new clusters were also reported by MOH on Sunday.

The first is linked to a chef in Changi Prison Complex who tested positive for the virus on May 13. There are four cases in this cluster, two of which - a 35-year-old cargo driver at Sats Food Services and a 22-year-old unemployed man - are household contacts of the chef.

The second cluster is linked to a cook at Wok Hey (White Sands) who was confirmed to have Covid-19 on May 13. There are three cases in this cluster, including a customer service officer at Wareesan Management who is a family member and household contact of two previously confirmed cases.

Meanwhile, the Changi Airport Terminal 3 cluster had six more cases, including a one-year-old Singaporean boy. He is a family member and household contact of a 44-year-old Singaporean man who works as a private-hire driver at Gojek and had visited the terminal on May 6. The man was confirmed to have Covid-19 on May 12.

A 39-year-old male Philippine national who works as a nurse at Ren Ci Nursing Home (Ang Mo Kio) also tested positive and was linked to the cluster.

He is a household contact of a 37-year-old male Philippine national who was also among the cases announced on Sunday. The man works as a sales representative at JR Life Sciences and had visited Changi Airport Terminal 3 on May 4.

MOH added on Sunday that it was making special swabbing arrangements for all tenants and staff who have been working at White Sands Mall and the Giant outlet at Block 440 Pasir Ris Drive 4 since May 2, as some visitors to these venues tested positive for the virus in the past two weeks.

There were also 17 unlinked community cases on Sunday, including a 29-year-old female Philippine national who works as a nurse at Raffles Hospital.

Six of the seven cases that tested preliminarily positive for the B1617 variant - which was first detected in India - were unlinked.

There were also 11 imported cases announced on Sunday.

Globally, the virus outbreak, which began in December 2019, has infected more than 163 million people. Over 3.37 million people have died.