Officials say an Indonesian police plane carrying 13 people lost contact during a flight on Saturday.
Police said the plane was headed to the island of Batam near Singapore when it lost contact midmorning about 50 minutes after take-off.
The plane was carrying five crew members and eight passengers.
Officials said rescuers were trying to locate the plane by searching seas between Mensanak and Sebangka islands.
A seat and bag containing a cellphone and police documents was located according to the chief of the National Search and Rescue Agency.
The Associated Press contributed to this report.