More than 6,000 people there are confirmed as either dead or missing, but thousands of others are still unaccounted for.

The Indian coastguard helicopter was flying low over Sentinel Island to drop aid when it came under attack.

A senior police officer said the crew were not hurt and the authorities are taking it as a sign that the tribes have not been wiped out by the earthquake and sea surges as many had feared.

The Andaman and Nicobar archipelago is home to several tribes, some extremely isolated.

Officials believe they survived the devastation by using age-old early warning systems.

They might have run to high ground for safety after noticing changes in the behaviour of birds and marine wildlife.

Scientists are examining the possibility to see whether it can be used to predict earth tremors in future.