JAKARTA, Jun. 7 -- Indonesia has seized a ship carrying 15 tonnes of illegal tin ore on its way to Malaysia from West Kalimantan in Indonesia, an Indonesian customs department spokesman said on Sunday.

The ship was captured by a customs patrol in Indonesian waters near Natuna on Saturday and did not have a permit for the cargo, said Evy Suhartantyo, a spokesman for the customs department at the finance ministry.

Indonesia has banned the export of tin ore and applied strict rules for exporting refined tin, including requiring smelters to source tin ore from legal mining.

Competition from traditional tin miners and environmental problems have forced the world's largest integrated tin-miner, PT Timah <TINS.JK> to reduce sourcing tin ore from its onshore mines in Bangka-Belitung islands, Indonesia's main source of tin.