Mexican authorities said there are no new deaths connected to the H1N1 swine flu virus and expressed hope that the spread of the virus is slowing down.

Health Secretary Jose Angel Cordova said Saturday the confirmed death toll remains at 16 with 443 confirmed cases.

Mexican and U.S. health officials warned Saturday it is still too early to determine if the worst is over.

The acting director of the U.S. Centers for Disease Control, Dr. Anne Schuchat, said she is "encouraged" by the news from Mexico.  The agency announced the number of confirmed U.S. cases climbed to 160 and the death toll remains at one.

A top World Health Organization official said Saturday there is no evidence the swine flu virus is spreading outside of North America in a "sustained" way.  But Dr. Michael Ryan said the organization still considers a pandemic "imminent" because the virus is spreading.

WHO reports the swine flu has spread to 17 countries with  615 confirmed cases.

The health organization said it has sent 2.4 million treatments of the anti-viral drugs to 72 developing countries to prepare for a possible pandemic.

In the United States, President Barack Obama said he has asked Congress for $1.5 billion dollars to develop a vaccine and buy more treatments.

The WHO said the virus has been confirmed in Italy, South Korea, France, Denmark, Hong Kong, Austria, Britain, Canada, Costa Rica, Germany, Israel, New Zealand, the Netherlands, Spain and Switzerland.  

The organization said it is not advising any restrictions on travel or border closures.  Nevertheless, several airlines have reduced flights to Mexico because of fears over the new flu.

Some information for this report was provided by AFP, AP and Reuters.