The Casa C-212 plane came down in a mountainous part of Sumatra on September 29, but bad weather and rough terrain had hampered rescue efforts.

The aircraft sent an emergency signal before disappearing from radar. The cause of the crash is not known.

There were four children among the passengers.

"Two teams were lowered to the crash site and they have confirmed that all 18 people on the plane have died," Indonesia's search and rescue head Sunarbowo Sandi announced on television on October 1.

He did not provide further details.

The aircraft crashed on the morning of September 29 near the North Sumatran village of Bahorok, about 70km (40 miles) from the city of Medan.

The plane's wreckage was spotted during aerial surveillance shortly afterwards.

Indonesia relies heavily on air transport and has a poor aviation safety record.

In May, 27 people died when a passenger plane crashed into the sea off the eastern province of West Papua.