The Health Ministry reported three new suspected Sars cases, including a four-year-old Singaporean boy and a British engineer, and said it had quarantined 728 people nationwide.

The ministry is also racing to track down 76 people who had visited a Sars-infected produce market in Singapore to prevent local transmissions, and warned they would be jailed if they did not report to authorities.

The ministry's deputy director-general Dr Mohd Ismail Merican said the boy, the youngest Sars patient here, lives with his grandparents in Malaysia and developed fever and cough after visiting his parents in Singapore.

The other two suspected cases involved a 26-year-old British engineer who works here and a 22-year-old cook from Perak, both who also fell ill after visiting Singapore earlier April, he told reporters.

Ismail said the number of people quarantined nationwide has surged to 728.

Four nurses isolated

They included 546 staff and patients in a mental institution in Sarawak which was sealed off over the weekend after a patient died of pneumonia and three others displayed Sars symptoms, he said.

A fifth patient was hospitalised after falling ill Sunday while 19 others including four nurses with respiratory problems have been isolated in separate wards in the institution, he added.

The government has also quarantined 133 out of more than 200 people who visited the Pasir Panjang market in Singapore, which has been shut down after a worker was diagnosed with Severe Acute Respiratory Syndrome (Sars), but 76 others could not be found.

"They are avoiding quarantine. These are a menace to our community. These are the people who cause the disease to spread," Health Minister Chua Jui Meng said.

"These people are greatly, grossly irresponsible and must be condemned by the community."

Malaysia has recorded six probable Sars cases including two deaths, but there has been no evidence of local transmission yet.

Chua expressed disappointment that Malaysians were still travelling to Sars-affected countries despite the high risks.

"They must realise they will adversely impact the community and their families. If they don't take the advice, they may die," he warned.-- AFP