The World Health Organization raised its global alert level Monday, signaling the swine flu virus was spreading from human to human in community outbreaks, but it stopped short of declaring a full-blown pandemic. The WHO announcement in Geneva followed a decision by the top EU health official urging Europeans to postpone nonessential travel to parts of the United States and Mexico because of the virus. Mexico health department spokesman Carlos Olmos confirmed the move by the WHO to raise the alert level from Phase 3 to Phase 4. Putting an alert at Phases 4 or 5 signals that the swine flu virus is becoming increasingly adept at spreading among humans. That move could lead governments to set trade, travel and other restrictions aimed at limiting the disease's spread. The WHO's Phase 6 is the pandemic phase, characterized by outbreaks in at least two regions of the world, Associated Press reported. U.S. Homeland Security Secretary Janet Napolitano said the United States is preparing as if the swine flu outbreak already is a full pandemic. The virus was suspected in up to 152 deaths in Mexico, the epicenter of the outbreak with more than 1,600 cases suspected, while 50 cases _ none fatal _ were confirmed in the United States. Worldwide there were 79 confirmed cases, including six in Canada, one in Spain and two in Scotland. The World Health Organization reported a slightly lower figure, 73. The WHO said it was still awaiting official reports from the U.K. about the Scottish cases, and it was reporting different numbers of cases in the U.S. and Mexico from what those governments confirmed. Russia, Hong Kong and Taiwan said they would quarantine visitors showing symptoms of the virus amid global concern about a possible pandemic.