The World Health Organization rushed to convene an emergency meeting Saturday to develop a response to the "pandemic potential" of a new swine flu virus that has sparked a deadly outbreak in Mexico and spread to disparate parts of the United States. Health officials reported that at least eight students at a private high school in New York City had "probable" swine flu, and confirmed three new cases - two in Kansas and one in California - bringing the total number of confirmed US cases to 11. The president of Mexico, where the outbreak has killed as many as 81 people, issued an order granting his government broad powers to isolate patients and question travelers. "This is a serious moment for the nation," President Felipe Calderon said Saturday. "And we are confronting it with seriousness, with all the pertinent measures." The director general of the World Health Organization, Margaret Chan, said the "situation is evolving quickly."