Obama says emergence of swine flu not cause for alarm

President Barack Obama said the emergence of swine flu in the U.S. is "not a cause for alarm," and the government is closely monitoring the outbreak, which is linked to at least 100 deaths in Mexico.

Obama, in a speech to the National Academy of Sciences in Washington, said the health emergency declared by his administration is a "precautionary tool" designed to free up resources to monitor and respond to the spread of the virus.

At least 20 cases of swine flu have been confirmed in the U.S., and Richard Besser, the acting director of the Centers for Disease Control and Prevention, said health officials expect more infections to begin showing up.

More than 100 people have died of flu-related causes in Mexico, and at least 20 of those have been confirmed as swine flu cases.

Health officials said six people in Canada also have been diagnosed with the disease and more cases are likely. New Zealand said as many as 13 students who recently visited Mexico may have swine flu.

Australia, Japan, Singapore and South Korea have begun screening travelers for fever, while Hong Kong raised its swine- flu response level to "serious" from "alert."

The U.S. also is monitoring travelers crossing the border for signs of sickness. The Department of Health and Human Services has declared a public health emergency and is releasing some stockpiles of anti-viral drugs.

"This is obviously a cause for concern, a heightened state of alert, but it's not a cause for alarm," Obama said today.

Swine flu is a respiratory disease of pigs caused by a type-A influenza virus that regularly leads to outbreaks among the animals, according to the CDC.