JAKARTA - President Joko Widodo will personally inspect the Chinese fishing boat detained by the navy for poaching in the waters off Indonesia's Natuna Islands, said a provincial official on Wednesday (June 22).

The visit will come days after Vice-President Jusuf Kalla indicated in an interview with Reuters that Indonesia would be more assertive in upholding its sovereignty over waters around the Natuna Islands.

Riau Islands Provincial Government spokesman Hery Mokhrizal told The Straits Times that the presidential delegation will arrive on Thursday to visit the naval base in Ranai, where the China-flagged Yueyandong Yu 19038 fishing boat and its crew of seven has been held for investigations since being detained last Friday.

Ranai is the capital of Natuna Regency, which is located in the Natuna archipelago of the South China Sea some 550km from the north-east of Indonesia's Batam island and less than 530km from Singapore.

Last Friday, the Indonesian Navy had intercepted and detained the Yueyandong Yu for fishing illegally in Indonesia's waters off the Natunas, in at least the third such incident involving a Chinese vessel since March this year.

The presence of these Chinese fishing boats poaching in the Natunas is a ruse by Beijing to stake its claims in the South China Sea, the naval commander of Indonesia's Western Fleet A. Taufiq R. said on Tuesday.

China claims to own almost all of the South China Sea while Vietnam, the Philippines, Malaysia and Brunei have overlapping claims. China's land reclamation works on disputed islands and reefs in the waterway as well as activities by its fishermen have escalated tensions in the region over the past year.

Indonesia is not a party to the disputes but grew concerned after Beijing in March said the waters around the Natunas, within Indonesia's exclusive economic zone, are part of its "traditional fishing grounds" and Chinese boats should be free to fish there.

In Friday's incident, the Indonesian navy said warning shots had to be fired to stop 12 Chinese fishing boats but it detained only the Yueyandong Yu and its crew because it was the only boat with its fishing nets cast at the time.

Rear Admiral Taufiq denied Beijing's allegation that shots fired by the Indonesian warship KRI Imam Bonjol had wounded a Chinese fisherman, calling it "baseless". Beijing has registered a strong protest, with Foreign Ministry spokesman Hua Chunying saying Indonesia's actions was “indiscriminate use of force”.

The Yueyandong Yu is among 57 foreign-flagged fishing boats held by Indonesia’s maritime authorities for poaching since the start of 2016, said the country’s Maritime Affairs and Fisheries Minister Susi Pudjiastuti.

Three of the boats are from China, 49 from Vietnam, four from Malaysia and one from Thailand.

The ministry has already blown up and sunk 176 fishing boats captured from poachers since October last year.

Ms Susi has vowed to continue to get tough with poachers, regardless of their nationality, adding that some 30 more of these illegal fishing boats, including one from China, will be blown up and sunk after Ramadan in July.