Mexico City  - Mexican authorities late Thursday revised upward the number of confirmed infections with the new variant of influenza A(H1N1) to 312.

Health Minister Jose Angel Cordova Villalobos said the number of confirmed swine-flu deaths remained at 12, but could not rule out that there were further cases among the total 159 influenza fatalities.

Further tests, to be conducted in the coming days, are expected to clarify whether that was the case, he added.

In an attempt to prevent a further spread of the infection, Mexico's government effectively ordered a five-day shut-down, suspending non-essential government business and also cancelling all official events during the May-Day weekend.

President Felipe Calderon urged all Mexicans to stay at home until Tuesday. In Mexico City, all restaurants and bars were ordered closed. Shops, supermarkets and pharmacies were to remain open. (dpa)