Singapore saw its sharpest single-day spike of 287 new coronavirus cases yesterday, bringing the total number of cases here to 1,910 as the global number of people infected crossed the 1.5 million mark.

Foreign workers in dormitories accounted for 202 of these new cases, but just as much of a concern was the spread of the virus in the wider community.

Health Minister Gan Kim Yong said yesterday that social gatherings are still taking place, with more than 10,000 written advisories issued over the past two days to those who did not observe safe distancing.

"This cannot continue," he said, appealing to Singaporeans to stay at home. He was speaking at a press conference yesterday, ahead of the long weekend.

He also disclosed that parents will no longer be allowed to drop children off at their grandparents' homes on a daily basis, in an effort to protect vulnerable seniors from becoming infected.

Children with both parents working in essential services should be left at childcare facilities as far as possible, although exceptions may be made on a case-by-case basis.

All stadiums will be closed from today, as people had continued to gather there in groups to exercise despite stricter rules on social distancing.

Enforcement efforts will be stepped up against those who continue to flout safe distancing measures, National Development Minister Lawrence Wong said.

To cut the chain of transmission in dormitories, thousands of foreign workers who are healthy - especially those working in essential services - will be moved to locations such as army camps, floating hotels and vacant Housing Board blocks, and testing for them will be ramped up.

Coordinating Minister for National Security Teo Chee Hean is now advising the task force tackling the situation in dormitories, said Mr Wong, noting that the police and Singapore Armed Forces (SAF) are also involved in operations.

Mr Wong said: "This is a very major and urgent issue that requires active intervention."

Three of yesterday's new cases were imported, and 217 of the local cases were linked to existing clusters. Links are also emerging between previously announced and new cases, with the S11 Dormitory @ Punggol now confirmed to have 283 cases.

Preliminary investigations have linked the cluster at Mustafa Centre with clusters at the construction site at Project Glory and five dormitories, said the Ministry of Health's (MOH) director of medical services Kenneth Mak yesterday.

The foreign workers are believed to have been infected after visiting Mustafa Centre, where some employees had fallen ill.

The workers then infected their co-workers, who subsequently infected others at their dormitories.

Mr Wong said: "Many had very mild symptoms and so they continued to work, that's why there was a delay in picking them up."

He added that it is likely the virus had been spreading in dorms for some time.

The SAF and police are working with the Manpower Ministry and dormitory operators to manage dorms, he said. This includes making sure workers' daily needs are taken care of and that they comply with safe distancing measures.

"We cannot rely solely on dorm operators any more given the current situation," Mr Wong said.

Hygiene in dorms will also be improved and contact reduced to prevent the spread of the disease.

Turning to the spread in the community, he added that despite circuit breaker measures kicking in on Tuesday, some people were still not following instructions to stay home.

"We hope that Singaporeans will comply, not just because of the enforcement efforts that are ongoing, but really out of a necessity for all of us to do our part and ensure that this circuit breaker truly has an impact on controlling the spread of the virus," he said.