A helicopter crashed into the Andaman Sea off Burma's western coast on Monday, killing three people.

Several other passengers were rescued and taken to hospitals. The exact number of survivors was not clear.

Malaysia's oil and gas company Petronas had rented the helicopter to fly to off-shore natural gas drilling rigs in the Yetagun gas and oil field.

Petronas is developing the Yetagun field in cooperation with Burma's Energy Ministry and British, Thai and Japanese companies.

Burma is one of the poorest countries in Asia. Its government controls sales of natural resources, such as oil, natural gas and timber, and relies heavily on them for revenue.