Three crew members were missing after a helicopter crashed into a valley when attending typhoon rescue in Taiwan's southern Pingtung County on Tuesday afternoon.

The helicopter crashed during a mission to deliver goods to villagers affected by the powerful typhoon Morakot, said Chen Chung-hsien, an official in charge of the relief operation.

Another helicopter and ground troops had been sent out to search for the crashed plane, Chen said.

Bad weather and the plane's long service years may have contributed to the crash, he said. It was delivered in 1976.

Morakot has left 23 dead and 56 missing in Taiwan.

(Xinhua News Agency August 12, 2009)