The United Nations continued its efforts to aid tsunami survivors, focusing on the urgent task of providing clean drinkingwater and health care for millions of people. UN Secretary GeneralKofi Annan has cut short his vacation to oversee UN humanitarian efforts.

The next step should be preventing the possible outbreak of deadly diseases, as well as providing the longer-term need for an early warning system, said the world body in New York.

UN Disaster Assessment and Coordination teams, including officials from the World Health Organization and other agencies, have already rushed to many of the stricken countries, while others are on standby for deployment where needed.

After offering 21.63 million yuan (about 2.6 million US dollars)in emergency humanitarian aid to Indonesia, Thailand, Sri Lanka and the Maldives, China decided Wednesday night to substantially increase its assistance to the tsunami-hit region.

During a joint meeting among leading officials from government departments, the participants decided to take further aid measures-- to set up medical treatment teams with more than 100 personnel which are ready to head for those countries within 24 hours in case they are needed.

The Ministry of Commerce will work with relevant departments toprepare and send the additional relief supplies.

US President George W. Bush said Wednesday that he's committed to helping the countries that were affected by the disaster "in the difficult weeks and months that lie ahead."

"The United States will continue to stand with the affected governments as they care for the victims. We will stand with them as they start to rebuild their communities. We will prevail over this destruction," Bush told reporters at his Texas ranch.

He said the United States, Australia, Japan and India would form a "core group" to lead relief efforts, and other countries would join the initiative.

The United States has already sent or promised 35 million US dollars in aid to nations devastated by the massive earthquake andtsunami.

France declared Wednesday that it is to allocate 15 million euros (about 19.5 million dollars) as international aid to the tsunami-hit countries.

"According to an agreement with the president of the Republic (Jacques Chirac), (French Prime Minister Jean-Pierre) Raffarin decided to give 15 million euros as France's contribution to the international aid for the region," Raffarin's office said in a statement.

Britain announced earlier in the day that it will allocate 21.3million euros (about 27.7 million dollars), while the German government will contribute 20 million euros (about 26 million dollars) to the stricken region.

The Spanish government said it is to approve on Thursday 50 million euros (65 million US dollars) in grants and loans to help South Asian countries in their reconstruction.

The state-run Fund for Development Aid will provide the 50 million euros, and the grants and loans in preferential financial terms will contribute to the reconstruction of infrastructure facilities destroyed by the tsunamis, said the Industry, Tourism and Trade Ministry on Wednesday.

Two medical teams, made up of doctors and nurses from the Portuguese non-governmental organizations, flew to Sri Lanka on Wednesday to provide humanitarian assistance to the survivors there.

Along with them, the teams brought 11.5 tons of materials, including medicines, food, tents and blankets.

According to the Tunisian state-run news agency, two planes departed Wednesday from Tunisia with humanitarian relief for Indonesia following last Sunday's earthquake and tsunami.

Early Sunday, an 8.7-magnitude earthquake in the Indian Ocean sent high waves crashing onto the shores of coastal Indonesia, India, Malaysia, Myanmar, Sri Lanka, Thailand, the Maldives and Bangladesh, and submerged villages and towns.