Mexico has revised down the suspected death toll from swine flu from 176 to 101, indicating that the outbreak may not be as bad as was initially feared.
Health Minister Jose Angel Cordova told the BBC that, based on samples tested, the mortality rate was comparable with that of seasonal flu.
Mexico has ordered a five-day shutdown in a bid to contain the virus.
A World Health Organization official said there was no evidence of sustained virus spread outside North America.
WHO Director of Global Alert and Response Dr Michael Ryan said the emergence of more cases in Europe did not mean the WHO would necessarily need to raise its global pandemic alert level.
"I think it would be, at this stage, unwise to suggest that, in any way, those events are out of control or spreading in an uncontrolled fashion," he told a daily press briefing.
"I think the next few days will tell as this develops."