JAKARTA • Indonesia sank dozens of impounded foreign boats to mark Independence Day, an official said yesterday, as President Joko Widodo steps up a campaign to stop foreign fishermen from "stealing" in its waters.

Since elected, Mr Joko has intensified a campaign to exercise Indonesia's maritime sovereignty, and has blown up and sunk scores of foreign vessels.

"Today, we offer 60 boats" to be scuttled in eight locations, Fisheries Ministry official Mas Achmad Santosa said. "This is a gift (for Indonesia) and goes to show our consistency in enforcing the law," he added.

But unlike past boat-sinking events, which were broadcast on national television, yesterday's ceremony was markedly toned down, with officials barring media coverage. They have also refused to disclose the vessels' countries of origin.

Previously, Indonesia has sunk boats from countries including China, Vietnam and the Philippines, with Beijing particularly angered by the gesture.

Tension between Jakarta and Beijing has escalated in recent months as Chinese fishing boats have clashed with Indonesian government vessels, prompting Mr Joko to visit the Natuna Islands on a warship in June.

On Tuesday, he pledged to defend "every inch" of Indonesia's land and maritime territory in a State of the Nation address.

Unlike several of its South-east Asian neighbours, Indonesia has long maintained it has no maritime disputes with China in the South China Sea and does not contest ownership of any territory there.

But Beijing's claims overlap Indonesia's exclusive economic zone - waters where a state has the right to exploit resources - around the Natunas.

AGENCE FRANCE-PRESSE