Donors pledged over $11.5 billion on Tuesday to fight AIDS, malaria and tuberculosis over the next three years but the head of the fund waging the battle said it was not enough to protect millions of people at risk.

Announcing the figure raised by a two-day conference in New York, U.N. Secretary-General Ban Ki-moon said the pledges send a powerful message but that funding demands were likely to outstrip even the impressive commitments made today.

Michel Kazatchkine, executive director of the Global Fund to Fight AIDS, TB and Malaria, noted that the pledges fell below the minimum of $13 billion the fund says is needed to sustain the fight against the killer diseases.

The outcome of this conference is absolutely key for millions of people around the world and this will not take us to where we were hoping to be, he said in a telephone interview.

The public-private Global Fund, based in Geneva, accounts for around a quarter of international financing to fight HIV and AIDS, as well as the majority of global funds to fight tuberculosis and malaria.

To date it has channeled $19.3 billion into 144 countries to support mass prevention and treatment programs against the three diseases, which together kill millions of people each year, most of them in the world's poorest countries.

Founded in 2002, the fund raises money from donors every three years and in 2007 secured $9.7 billion for 2008-2010.

Tuesday's replenishment meeting -- at which more than 40 countries, private foundations and corporations were asked to make pledges -- was designed to attract at least $13 billion, with hopes for up to $20 billion for the years 2011 to 2013.

HARD TIMES

With the pledges so far falling short, Kazatchkine said the Global Fund's progress would suffer and the internationally agreed Millennium Development Goals (MDGs) on reducing poverty and ill health would not be met by the 2015 target date.

Kazatchkine acknowledged that a global economic recession has made times hard for donors, but said political priorities still had to be set. In the end it's still a political choice whether you invest in development or in other areas, he said.

Progress has been made in fighting the three diseases in recent years, with around 5.2 million people with HIV now getting access to the AIDS drugs they need, and projects to fight malaria saving more than 750,000 lives in the past 10 years.

The Global Fund says programs financed by it have so far put 2.8 million people on treatment for HIV/AIDS, allowed 7 million people to be treated for TB and allowed 122 million mosquito nets to be distributed to prevent malaria infection.

PALTRY SUM

Advocacy groups were scathing about what they considered the paltry sum pledged. Doctors Without Borders said the decision by donors to massively underfund the Global Fund will cost lives and severely weaken the ability of countries to implement programs to beat back the diseases.

Asia Russell of Health GAP called the New York conference a flop.

A number of countries increased their commitments, including the United States, which pledged $4 billion, remaining the largest contributor to the Fund.

But Eric Goosby, the Obama administration's chief AIDS official, called for major reforms in the way the organization carries out its work. We need to drive needed reforms and ensure that smart, effective investments are being made, Goosby told a telephone news conference.

Other countries praised by Kazatchkine and U.N. chief Ban for boosting their donations included France, Japan, Canada, Norway and Australia.

For some governments it has been a very difficult decision to take in the face of budget restrictions. I know that some leaders really faced a lot of internal resistance, and yet they made bold commitments, Kazatchkine said.

He added that he hoped Tuesday's pledges would not be the final word and he would be looking for any opportunity to persuade governments to top up their contributions.

Medicine