The World Health Organization has decided to move its A/H1N1 flu alert level to phase six as the number of reported infections climbs to nearly thirty-thousand. It's the Organization's first global flu pandemic declaration in 41 years.

The decision was made Thursday following a teleconference with world experts.

Dr. Margaret Chan, WHO Chief, says she is moving the world to phase 6, the agency's highest alert level. It means a pandemic is under way.

Dr. Chan said, "With the announcement of phase 5 to phase 6 clearly it sends an important message to countries that, irrespective of what stage of the epidemic is in their country they must maintain continuous vigilance."

The WHO has stressed that most cases are mild and require no treatment, but the fear is that a rush of new infections could overwhelm hospitals and health authorities, especially in poorer countries。

(Video from CCTV.COM)