JAKARTA, Indonesia >> An Indonesian patrol ship confronted a Chinese coast guard vessel that spent almost three days in waters where Indonesia claims economic rights and are near the southernmost part of China’s disputed South China Sea claims.

The Indonesian Maritime Security Agency said it detected Chinese ship 5204 entering Indonesia’s exclusive economic zone in what Indonesia calls the North Natuna waters on Friday night.

The agency sent a patrol ship that closed within 0.6 miles of the Chinese coast guard vessel and they communicated to affirm their position and their nation’s claims to the area, said Aan Kurnia, chief of the Indonesian Maritime Security Agency.

“We asked them to move out as it was Indonesia’s EEZ. But they insisted that it is China’s nine-dash- line territory. Our officers at the vessel argued with them until they moved out,” Kurnia said. He said he reported the incident to Indonesian government ministers.

“The Chinese coast guard vessel finally left the North Natuna Sea on Monday at 11:20 a.m.,” he said.

Chinese foreign ministry spokesperson Wang Wenbin indicated that China saw nothing wrong with the ship’s actions and said the two countries are in contact over “relevant maritime issues.”

“China’s rights and interests in the relevant waters of the South China Sea are clear,” Wang said at a daily briefing on Tuesday. “As far as I know, Chinese coast guard vessels have been performing normal patrols in the waters under China’s jurisdiction.”

China’s “nine-dash line” delineates its claim to virtually the entire South China Sea. A 2016 international arbitration ruling involving the Philippines invalidated most of China’s sweeping claims in the sea, but China has ignored the ruling and called it a sham.

Indonesia does not have a territorial claim to the South China Sea, but a section of Indonesia’s exclusive economic zone that includes natural gas fields lies within China’s “nine-dash line.” Chinese ships have regularly entered the area Indonesia calls the North Natuna Sea, causing tensions between the countries.

China has in the past explained its presence in those waters on the basis of “traditional fishing rights.”

Chinese ships also regularly patrol off the island of Borneo and near James Shoal east of the Natuna islands, China’s southernmost territorial claim which Malaysia says belongs to it.

The South China Sea accounts for more than 10% of the global fish catch and surrounding states have taken increasingly extreme measures to ensure they obtain their share. Stocks have declined drastically amid overfishing and the destruction of coral reefs, to the point that they may be on the verge of collapse, according to some studies.

The Indonesian patrol ship KN Pulau Nipah 321 has been deployed for such patrols in Indonesia’s western maritime zone until November.

The Indonesian Foreign Affairs Ministry has communicated to the Chinese Embassy in Jakarta to explain the coast guard’s presence, spokesperson Teuku Faizasyah said.