AIDS was the most globalised epidemic that humanity had known, the UN secretary general, Mr Kofi Annan, said at the opening of a major two-day conference on HIV/AIDS organised by the Government as part of Ireland's European presidency.
Speaking by video-link to delegates in Dublin Castle, including health and development ministers from 55 countries in Europe and Central Asia, Mr Annan said it was "a deadly mistake" to believe AIDS was mainly an African problem, or that it only affected people on the margins of society.
"In the past five years it has grown faster in eastern Europe and central Asia than in any other part of the world. In eastern Europe, 80 per cent of new infections are among young people," he said.
The Taoiseach, Mr Ahern, told the conference, which is focusing specifically on Europe and central Asia, that the growth of AIDS in the region was "explosive".
However he added that "early and decisive political action from the top" could halt the epidemic in its tracks.
"This Dublin conference must send out a clear message. HIV/AIDS is a potent threat to our young people. It continues to spread in our region at a rate which should give cause for alarm. It is time to take strong political action nationally, regionally and internationally," Mr Ahern said.
The Minister of State for Development Co-operation and Human Rights, Mr Tom Kitt, who is chairing the conference, called on the EU to appoint a special ambassador to promote greater internal coherence and co-ordination on HIV/AIDS.
There was some sharp criticism of the EU's role from guest-speaker Bob Geldof, particularly the European Development Fund.
He claimed there was "$14 billion lying in the fund for the past two decades" which could be used in the battle against AIDS in Africa and elsewhere.
Asked to comment later at a press conference, Mr Kitt said: "There is a very lively discussion taking place on this very issue."
He added: "The Irish presidency is taking the views expressed here very seriously, and we intend dealing with this issue."
The executive director of the UNAIDS agency, Dr Peter Piot, said: "I fully endorse what Bob says about the EDF."
The President of Portugal, Dr Jorge Sampaio, pointed out at the press conference that "I am the only head of state of the EU who is here today".
He supported the sentiments expressed by Archbishop Desmond Tutu earlier that "silence kills. Stigma kills. Speak up, speak up, speak out."
Ms Deirdre Seery, director of the Alliance Sexual Health Centre in Cork, who is also a member of the Government's National AIDS Strategy Committee, said the conference marked "a big step", but continuity was essential.
"There is a fear that once the Irish presidency passes, the energy will go out of it, and it will just be a bit of paper on the shelf."
The proposal for the EU to appoint an AIDS ambassador made sense. "What's happening in Europe now could turn into what's happening in Africa."
A broad approach was required. "We need a world solution."
AIDS activist Mr Julian Hows said there was "blatant and also latent discrimination" across Europe against people who were living with HIV and AIDS.
He complained that "a great many" governments had failed to include representatives of civil society among their delegations, against the recommendation of the Irish Government.
Delegates were working late into the evening on the text of the proposed Dublin Declaration, due to be adopted by the conference this afternoon.
The final version will set out specific targets on HIV/AIDS, and dates for achieving them.