GENEVA, June 11 (Xinhua) -- The World Health Organization (WHO) has made the decision to move its A/H1N1 pandemic alert level to phase six, and will declare soon the widely spreading A/H1N1 influenza had developed into a full pandemic, diplomatic sources said on Thursday.

    The decision was made following consultations with world experts through a teleconference, the sources said.

    A WHO statement on the decision has been sent to the WHO's members, and the WHO chief is to hold a news conference at its Geneva headquarters to announce the organization's official decision at 1600 GMT Thursday.

    The declaration is expected amid concerns that the A/H1N1 flu virus, which originated from Mexico two months ago, has widely spread to Asia, Europe, and the Americas.

    The WHO has raised the alert level to five at the end of April, the penultimate level in its six grades, indicating a pandemic was "imminent." And many experts have been expecting the upgrade of the flu due to its fast-spreading nature.

    However, experts explained that the highest level by no means indicates the greatest severity of the disease, but simply indicates the geographical spread of this flu.

    This is the first global flu epidemic in 41 years. As of Wednesday, 74 countries have officially reported 27,737 A/H1N1 infection cases to the WHO, including 141 deaths.