The flu virus also spread further across the globe, with more cases confirmed in Asia, Europe and Mexico, as the World Health Organization (WHO) said there were 615 cases of swine flu in 15 countries.

"I believe we have enough elements to say that we are in a stabilization phase," said Mexican Health Minister Jose Angel Cordova, who confirmed that the tally of cases, including those who have died, had risen to 443.

Mexico, and particularly its capital, has been at the epicenter of the flu outbreak, recording most of the infections worldwide and all the deaths except for one -- a Mexican toddler visiting relatives in the United States.

In Geneva, a WHO official indicated that the severity of the new virus in Mexico had not yet been established and that it had not spread in a sustained way outside of the Americas, a condition necessary to declare a full global pandemic.

"We see no evidence of sustained community spread outside North America," said Mike Ryan, WHO Director of Global Alert and Response.

The WHO raised its alert level to five on a scale of six Wednesday, indicating that a pandemic was imminent.

Despite signs that the outbreak in Mexico may be stabilizing, the United States was not letting down its guard.

"We can't afford to let down our vigilance," said Anne Schuchat, a top official at the US Centers for Disease Control and Prevention (CDC), indicating that the US now has 160 confirmed cases spread across 21 states. "I will not be surprised if we find additional cases or additional deaths."

President Barack Obama and his Mexican counterpart Felipe Calderon discussed the outbreak in a telephone call on Saturday, the White House said.

The two leaders "spoke for 20 minutes this afternoon to share information about each country's efforts to limit the spread of the 2009 H1N1 flu strain and the importance of close US-Mexican cooperation," the White House said in a brief statement.

The US government has taken preventative measures, including delivering a quarter of the 50-million-dose national stockpile of the antiviral drugs Tamiflu and Relenza, and has launched public awareness campaigns, using Facebook, MySpace and Twitter.

In Canada, some 30 new cases were reported on Saturday, bringing the total number of people infected throughout the country to over 85.

South Korea, Ireland and Italy confirmed their first cases of the A(H1N1) virus, but all three countries said their patients had made swift recoveries.

Doctors in Norway were testing a woman who recently returned from Mexico for the virus to determine whether she could become the Scandinavian country's first case.

Hong Kong meanwhile confirmed a 25-year-old Mexican who arrived from Mexico via Shanghai had brought the first case of swine flu into a city living in fear of a repeat of the SARS virus and bird flu outbreaks of recent years.

Mexico's foreign minister advised Mexican citizens to avoid travel to China due to "unjustified" health measures being taken there against Mexicans.

Police on Friday sealed off the Hong Kong hotel where he had briefly stayed and placed the building and more than 300 guests and staff under a seven-day quarantine.

The case sparked a regional alert, with China immediately ordering health authorities to track down and isolate the man's fellow passengers, while some pharmacies in Hong Kong sold out of face masks.

India and Japan also reported suspected cases, with Japanese authorities saying a four-month-old baby from the United States was being tested.

The alarm caused by the flu was evident in Egypt, which began slaughtering its 250,000 pigs began despite the WHO insisting there was no evidence that the animals were transmitting the virus to humans.

Benin became the second African country to report a suspected case of the flu as Health Minister Issifou Takpara told AFP that a European woman may have contracted the virus during a trip in Mexico.

British officials confirmed two new cases, bringing the total to 15, including one person who appeared to have been infected in Britain by someone recently returned from Mexico.

Britain launched a public information campaign on Thursday, with adverts on television, radio and in newspapers underlining the need to take basic hygiene precautions, such as using tissues and washing hands.

Israel reported a third case -- a man recently returned from Mexico -- while confirmed cases in Spain rose from 13 to 15. German officials said a patient had infected a fellow patient and a nurse, bringing the number of cases there to six.

But health authorities said the world appeared better prepared to fight an epidemic than a few years ago, and promised that a vaccine was only months away.

"We have no doubt that making a successful vaccine is possible in a relatively short period of time," Marie-Paule Kieny, director of WHO's Initiative for Vaccine Research said Friday. Vaccine production, she added, could take four to six months.

Most cases outside Mexico have involved only mild symptoms of the illness treatable with existing flu medicines.

Some experts have suggested the virus may have weakened as it was carried outside the country.

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