The Singaporean health authorities on Monday lowered its alert level for influenza A/H1N1from "orange," next to the highest "red," to "yellow."

According to local radio 938live, the country's Health Ministry urged Singaporeans to maintain alertness and vigilance, adding that stringent border controls will still be maintained with temperature screening at air, land and sea checkpoints.

Singapore has investigated 33 flu cases so far. All the cases have tested negative for the flu A/ H1N1 virus except for one pending laboratory confirmation.