Seven European countries had confirmed cases of people infected with swine flu as of Thursday afternoon, the European Centre for Disease Prevention and Control (ECDC) said.

Just over half the 25 European cases were reported from Spain with 13 confirmed, the agency said.

Other European countries impacted were Britain (5), Germany (3), Austria, the Netherlands and Switzerland with one each, along with a "probable case" in France, Denis Coloumbier, head of the ECDC preparedness and response unit, said at a briefing.

Outside Europe, the tally included 49 cases in Mexico and seven deaths, 91 in the United States, 19 in Canada, 14 in New Zealand, two in Israel, two in Costa Rica and one in Peru, the ECDC said.

The ECDC backed the decision by the World Health Organization late Wednesday to raise the pandemic alert level for the swine flu virus it prefers to call novel influenza virus A(H1N1).

However, it is just a question of time before the level is raised to the highest one, Professor Angus Nicoll, head of the ECDC's influenza programme, said, citing the progression of a pandemic.

The ECDC with headquarters in Sweden began to operate in 2005, and includes all 27 EU states as well as several non-EU members.

While the current outbreak so far "doesn't look as bad as that of 1918-1919," Nicoll said, he added that it "doesn't mean it will not be of considerable impact."

He noted that even "mild" seasonal influenza is estimated to claim some 40,000 lives in the EU every year and puts "a lot of stress on the health systems."