Jakarta: Indonesian authorities on Monday accused China of violating its territorial waters, after Chinese coast guards entered a region claimed by Jakarta near the South China Sea. Indonesian Foreign Minister Retno Marsudi lodged a protest with the Chinese ambassador, after summoning him over the incident that occurred on Saturday in Natuna Islands, situated to the north of Borneo islands, Efe news reported. According to the Indonesian government, Chinese coast guards entered the region for a Chinese fisherman, who was detained by an Indonesian patrol boat while fishing in the eastern waters of the archipelago, considered a special economic zone by Jakarta. According to the website Detik, Marsudi protested the violation of Indonesia's sovereign rights and jurisdiction by Chinese coast guards, and sought explanations from the Chinese ambassador. He also stressed that Indonesia is not part of the territorial disputes in the South China Sea, a region claimed in almost its entirety by China, and partly by Brunei, the Philippines, Malaysia, Taiwan and Vietnam. Tension in the South China Sea has increased in recent years amid altercations and accusations between the disputing parties, who have also increased their military presence in the region.