AKIPRESS.COM - Indonesia's foreign minister said on Friday a halt on coal shipments to the Philippines will continue until Manila guarantees security in its waters after seven Indonesian sailors were taken hostage, the latest in a string of abductions.

Indonesian authorities are concerned that piracy in the Sulu Sea area, a major sea traffic corridor for the world's top thermal coal exporter, could reach levels previously seen in Somalia, Reuters reports.

In April, the Indonesian Navy instructed all commercial vessels to avoid piracy-prone waters around the southern Philippines.

Analysts say $40 billion worth of cargo passes through those waters a year, including supertankers from the Indian Ocean that cannot use the crowded Malacca Strait.

"The Indonesian government has decided that the moratorium on coal exports to the Philippines will be extended until there is a guarantee for security from the Philippines government," foreign minister Retno Marsudi told reporters.

Indonesia supplies 70 percent of the Philippines' coal import needs, which Indonesian data shows stood at about 15 million tonnes, worth around $800 million, last year.

Alarmed at the frequency of attacks, port authorities in some areas of Indonesia, particularly Kalimantan on the island of Borneo, have stopped issuing permits to ships taking coal to the southern Philippines.

Philippine officials said the government had been working to address piracy in the south and that coal importers could tap other suppliers.