MEXICO CITY — A top Mexican medical officer accused the World Health Organization of being slow to respond to the country's warning about a health crisis that turned into a global swine flu scare. The WHO disputed the claim.

Dr. Miguel Angel Lezana, Mexico's chief epidemiologist, told The Associated Press late Thursday his center alerted the Pan American Health Organization, a regional arm of WHO, on April 16 about an unusually late rash of flu and pneumonia cases in Mexico.

But he said no action was taken until eight days later, when the WHO announced it was worried the outbreak could become a pandemic.

"It seems it should have been more immediate," Lezana, director of the National Epidemiology Center, told AP in a telephone interview. He called for an investigation into WHO's handling of the crisis.

WHO officials said today the agency learned April 9 of cases of "suspicious influenza" from Mexico and responded quickly on April 24 when U.S. and Canadian laboratories identified the virus as a new strain of flu.

"We moved into operation within a matter of hours," WHO spokesman Thomas Abraham told reporters.

Mexican health authorities came under criticism, particularly from frustrated citizens, for a slow and bumbling early response to the outbreak.

Hong Kong's leader said today the territory has a confirmed case of swine flu, Asia's first. In the United States, the confirmed case count stood at 132, and state laboratories believe the numbers are even higher. Hundreds of U.S. schools were closed Thursday.

In Mexico, the outbreak's epicenter, new cases and the death rate were leveling off, the country's top medical officer said. Health authorities said they have confirmed 300 swine flu cases and 12 deaths due to the virus.

"The fact that we have a stabilization in the daily numbers, even a drop, makes us optimistic," Mexican Health Secretary Jose Angel Cordova said. "Because what we'd expect is geometric or exponential growth. And that hasn't been the situation."

The only confirmed swine flu death outside Mexico was a Mexican toddler who died in a Texas hospital Monday.