Mayor Michael Bloomberg announced Monday that 28 students at a private Catholic school in Queens have contracted swine flu, and another 17 cases at the school are probable.

Bloomberg and Department of Health Commissioner Thomas R. Frieden said the cases at the St. Francis Preparatory School are mild and that all the students are recovering. Some of the school's students had visited Mexico on a spring break trip two weeks ago.

Bloomberg urged the city to stay calm and said New Yorkers "refuse to let fear dictate our lives."

The World Health Organization says the swine flu virus is now suspected in up to 149 deaths in Mexico, the epicenter of the outbreak. Forty cases total, none fatal, have been confirmed in the United States. Six others have been reported in Canada.

The top EU health official has urged Europeans to postpone nonessential travel to parts of the United States and Mexico because of the swine flu virus, and Spanish health officials confirmed the first case outside North America.

AP wire services were used in this report.