Kuala Lumpur  - Malaysia's Health Ministry placed its disease control division on alert to detect any signs of possible cases of the deadly swine flu virus in the country, news reports said Monday.

Hospitals and medical doctors have been asked to report cases with symptoms of influenza-like illness and severe pneumonia, said the ministry's director-general Mohamad Ismail Merican.

"The ministry is also filtering those entering the country or Malaysians who have visited Mexico, California or Texas after April 17, for signs of being infected by the swine flu," Mohamad Ismail was quoted as saying in a statement released by the official Bernama news agency.

Immigration officials said they have yet to receive orders to initiate border checks on those entering from countries hit by swine flu, but all entry points have been placed on standby.

The government has also warned Malaysians to avoid travelling to Mexico, where the deadly virus was believed to have originated.

"My advice is that unless they absolutely need to go to Mexico for work, they should wait a while until the health situation stabilized," said Tourism Minister Ng Yen Yen.

At least 20 people are confirmed to have died in Mexico from swine flu and more than 60 others have died from what is suspected to be the same viral disease.

The flu has spread to the United States, where 20 cases have been confirmed but no deaths reported. (dpa)