A mosque remains standing amid the rubble in Teunom, Indonesia.

Aceh has borne the brunt of the earthquake and the sea surges it triggered, with whole towns destroyed and tens of thousands of lives lost.

Mr Powell said the devastation was unlike anything he had seen before.

A huge aid effort is under way in the area. Mr Powell will attend a donors' conference in Jakarta on Thursday.

He flew by helicopter over Aceh's ruined provincial capital.

"I have been in war and I have been through a number of hurricanes, tornados and other relief operations, but I have never seen anything like this," he said.

The death toll in Indonesia is currently more than 94,000, and is expected to rise further.

In total, about 140,000 people have been confirmed dead in a dozen countries.

In other developments:

• Germany increases its aid pledge to tsunami victims from $27m to $670m - becoming the biggest contributor to the relief effort

   

• UK Prime Minister Tony Blair says the UK government will spend "several hundred million" dollars on relief and reconstruction efforts in the coming weeks

   

• European Union countries are observing a three-minute silence at midday on Wednesday to honour the victims.

   

• Shops re-open in villages in eastern Sri Lanka for the first time since the waves hit on 26 December

   

Decimated

In Indonesia, the relief effort is concentrating on towns and villages along Aceh's western coast, which have been devastated.  In

Not many buildings are left standing in Meulaboh

The BBC's Andrew North, who has visited the remote town, says only a handful of relief teams are working there, and with so much of the area destroyed, their impact is inevitably limited.

Thousands are living in increasingly dire conditions in a makeshift camp, with just two toilets.

Rubbish is piled up next to pools of water from recent rainfall which people use to drink, wash and cook.

Exploitation fears

Mr Powell, who is on a tour of tsunami-hit countries, has reiterated Washington's commitment to reconstruction.

The US has sent warships, aircraft and medical team to take part in an international effort to send aid to survivors in Indonesia and other affected countries.

The Pentagon has said it may double to 90 the number of its helicopters being used.

Powell said humanitarian relief was part of "American values"

Mr Powell has now gone to Jakarta, where he will join UN Secretary General Kofi Annan and senior politicians from around the world in Thursday's donors' meeting.

Participants will focus on co-ordinating the aid and recovery efforts.

About 500,000 survivors have been left homeless in Indonesia alone.

The total across affected countries has been estimated at five million.

The Jakarta meeting is also likely to consider establishing a tsunami alert system for the Indian Ocean region.

It's great how much money is being contributed - I think the bigger challenge is implementing the use of it Raj, Washington, USA

The UN children's agency, Unicef, has highlighted the plight of what it calls the "tsunami generation" of young victims.

Unicef urged donors to provide them with food and water and protect them from exploitation.

The Indonesian government has banned children from leaving the devastated province of Aceh after Unicef warned that child traffickers could be trying to exploit the situation.

And in the southern Indian state of Andhra Pradesh, a Save the Children Fund worker told the BBC of concerns that children were being taken away from relief centres by strangers.

CONFIRMED DEATH TOLLS 1. Indonesia: 94,081 2. Sri Lanka: 30,229 3. India (inc Andaman and Nicobar Is): 9,479 4. Thailand: 5,246 5. Somalia: 142 6. Burma: 53 7. Maldives: 74 8. Malaysia: 67 9. Tanzania: 10 10. Seychelles: 1 11. Bangladesh: 2 12. Kenya: 1