UNITED NATIONS, Jan 4: UN Secretary General Kofi Annan called on the donor nations on Tuesday to keep their pledges to Asian earthquake and tsunami victims as he left for Indonesia.

International donors have so far pledged more than $2 billion for relief and reconstruction in 11 Indian Ocean nations devastated by an earthquake and subsequent tsunamis last Sunday. Mr Annan's concern was important because in the past governments and financial institutions have failed to follow through on their pledges.

In an editorial 'Raining money', The New York Times noted: "The Bush administration is notorious for promising wonderful pots of money when the cameras are rolling - the Monterey summit meeting on poverty nearly three years ago comes to mind - and then failing to follow through once the attention fades."

It also pointed out "Mr Bush announced a Millennium Challenge Account to give African nations development assistance of up to $5 billion a year. We're still waiting for the account to actually hand out so much as a dollar."

The UN Children's Fund (Unicef) Executive Director, Carol Bellamy, on Tuesday called for four basic measures to "give this devastated tsunami generation a fighting chance".

These are: a focus on keeping children alive with an emphasis on clean water, adequate sanitation, basic nutrition, and routine medical care; caring for separated children, reuniting those who have lost their immediate families with their extended families and communities; ensuring that children are protected from exploitation; and helping children cope with their trauma by getting them back in school as soon as possible.

"I'm not satisfied that the global relief effort is focused enough on the more than million children made vulnerable by this calamity," Ms Bellamy said. "It's been a physically, emotionally and logistically challenging week for everyone involved in the response effort, but if anything we need to push ourselves to the next level of urgency."

Earlier estimates put the number of children killed by the tsunami at a-third of the total, but yesterday in Sri Lanka Ms Bellamy said this might be too low since children in relief camps formed too small a proportion of survivors.

Meanwhile, the Director-General of the UN World Health Organization (WHO), Lee Jong-wook, has arrived in the Indonesian capital of Jakarta, where on Thursday Mr Annan will launch a flash appeal at the global conference at the start of a five-day visit to the worst-hit of all the devastated countries as well as to Sri Lanka.

"The most urgent health need now is to prevent outbreaks of infectious disease, and particularly of water-borne diseases such as diarrhoeal diseases, dysentery and typhoid. It is clear that providing clean water to as many as possible of the affected communities is now the most pressing health priority," the WHO said.

"It is a race against time to act quickly to respond to disease outbreaks," it added, stressing not only the vital need to provide clean drinking water but also tending to the injured, improving sanitation in temporary shelters and ensuring the right assistance reaches the right people.

"Millions of people are now under serious threat of disease outbreaks as a result of damaged water and sanitation systems, sea water contamination and the congested and crowded conditions of the displaced," it warned, although no epidemic outbreaks have been reported so far.

"This is indeed a very special situation," UN High Commissioner for Refugees (UNHCR) Ruud Lubbers stated. "The dimensions of this disaster are enormous and it makes sense for an operational agency with UNHCR's experience to be available as part of the United Nations international relief effort. We all have a duty to help."

He said the agency, whose mandate is to protect, assist and find solutions for refugees fleeing persecution and conflict, had taken the exceptional decision to provide its resources and operational expertise to help natural disaster victims because of the immensity of the crisis.

The UNHCR has already begun an airlift to bring 400 tons of emergency aid to 100,000 people in Aceh, the most devastated of all the affected regions. "We face huge logistical challenges in Aceh, where we are starting operations from scratch," UNHCR spokesman Ron Redmond told a news briefing in Geneva on Tuesday.

The agency will focus on providing shelter, particularly in the remote and inaccessible regions in the west. "We're looking at the possibility of using both helicopters and barges to do this," Mr Redmond added.

"First priority is to get emergency shelter materials and other non-food basics to those living in the open. Next we'll get them shelter kits so they can begin rebuilding and repairing their homes." More than 155,000 people are believed to have died in one of the worst disasters ever to have hit the region.