The number of killer swine flu cases identified in Queens jumped from eight to 28 overnight, but no one is gravely ill, officials said today.

Mayor Bloomberg said another 17 possible victims are being monitored but added all the cases are associated with the St. Francis Prep school in Fresh Meadows.

"We have one reported cluster of swine flu at one school," Bloomberg said.

He said calls to every intensive care unit in the city turned up no one who is sick with the flu.

Dr. Richard Besser at the federal Centers for Disease Control said the jump in the Queens numbers "represents additional testing, not a spread of that cluster."

About 100 students and parents at the school are believed to have been infected with the flu. Only one person was hospitalized and has recovered.

The CDC said there are now 40 cases in America, none serious.

The World Health Organization said the killer flu was spreading globally.

"WHO is very concerned about the number of cases that are appearing, and the fact that more and more cases are appearing in different countries," said WHO spokesman Paul Garwood.

In Mexico, the national school system was shuttered after the death toll reached 149.

Mexico remains the only country where anyone has died of the virus, but U.S. officials warn they illness is likely to start killing people here, too.

"Thankfully, so far we have not seen severe disease in this country as we have seen in Mexico," Besser said. "I wouldn't be overly reassured by that."

Besser urged parents to prepare for the possibility of school closings and businesses to plan for a day when many employees can't come to work.

He urged Americans to wash their hands frequently, avoid crowds if possible and stop "giving that little kiss of greeting right now."

Masks, he said, are not needed yet.

President Obama, announcing new federal funding for scientific research, said it wasn't time to panic.

"This is obviously a cause for concern and requires a heightened state of alert. But it's not a cause for alarm," he said.

He said Sunday's declaration of a national public health emergency was just "a precautionary tool to ensure that we have the resources we need at our disposal to respond quickly and effectively."

Meanwhile, red-faced Republicans tried to explain why they stripped $780 million for pandemic flu preparedness from the economic stimulus package passed by Congress earlier this year.

As cases of the killer flu popped up around the world, officials in the European Union and India advised their citizens against traveling to New York City or Mexico.