Indonesia has sunk 34 impounded foreign boats, the latest bid to deter vessels from illegally fishing in the world's biggest archipelago nation.
The empty boats from Thailand, Vietnam, the Philippines and Malaysia were sunk as part of events to celebrate 70 years since the proclamation of Indonesian independence. Independence Day fell on Monday (local time) and was marked by nationwide celebrations.
All the vessels, which were blown up or scuttled at several locations across the archipelago of more than 17,000 islands, had been caught illegally fishing in Indonesian waters.
Indonesian President Joko Widodo is leading the campaign against illegal fishing and says it costs the country billions of dollars in lost revenues every year.
Foreign trawlers had already been sunk on several occasions in recent months.
"We have to be able to show that we can be triumphant on the sea because the sea is the future of our nation," Fisheries Minister Susi Pudjiastuti, a key figure in the campaign to stop illegal fishing, said in a statement on Tuesday after the latest sinkings.
Four Indonesian boats that had been caught fishing without correct documents were also sunk on Tuesday.
Five of the boats were blown up with dynamite while the others were scuttled, said Asep Burhanudin, a senior official at the maritime affairs ministry.
The decision to scuttle most of the boats followed concerns from green groups about the environmental impact of blowing up vessels, the government's preferred method in the past.
Burhanudin said the boats that were scuttled could act as artificial reefs for fish.