MEXICO CITY -- Mexico ordered schools and universities closed across the country, affecting some 33 million people, as the death toll from a swine flu epidemic that has terrified the nation rose to a suspected 149, officials said on Monday.

The toll increased from 81 deaths early Sunday to 149 by midday Monday. Twenty of the deaths have been conclusively tied to the flu, though officials say most of them are likely from the bug.

"We are in the most critical moment of the epidemic. The number of cases will keep rising," said José Ángel Córdova, the Mexican health minister.

Officials believe the virus has caused deaths in 10 Mexican states and probably spread through the entire country. As of Monday some 2,000 people nationwide had been hospitalized with pneumonia, a respiratory disease that can be caused by the virus -- a jump of around 400 from Sunday. Just over half the patients have already been treated and released, officials said.

On the 14th day of his vigil outside Mexico City's main hospital for respiratory illnesses, José Luis Fuentes, a 50-year-old auto-body shop worker, got some good news about his stepson. Ricardo Jarquin, 33, has been in intensive care since coming down with influenza.