China and Taiwan sparred on Wednesday over the legality of Chinese coast guard patrols to the east of the island, after the government in Taipei said merchant ships had been "harassed" close to its waters.
China, which views democratically governed Taiwan as its own territory, was angered after Japan and the Philippines said last month they would begin formal talks on their maritime boundaries, viewing that as involving waters off Taiwan.
Late on Saturday, Chinese state media reported ships had been sent to carry out a "special maritime traffic law-enforcement operation" in the waters east of Taiwan in response to the Japanese and Philippine announcement.
Taiwan said those ships had in recent days been "harassing" commercial shipping by asking them for information about their point of origin and destination and claiming jurisdiction.
"The relevant mainland authorities' law-enforcement patrols in the relevant waters are a just act to safeguard national sovereignty and maritime rights and interests," Zhang Han, a spokesperson for China's Taiwan Affairs Office, said in Beijing.
The Chinese coast guard is conducting "law-enforcement patrols" in the waters east of Taiwan in accordance with the law, and China will continue to strengthen its control over those waters, she said.
The patrols have angered Taiwan's government, which rejects Beijing's sovereignty claims, saying only the Taiwanese people can decide their future.
Speaking to reporters in Taipei on Wednesday, Taiwan Foreign Minister Lin Chia-lung said China was "using so-called 'law enforcement' as a pretext to pursue expansion".
"The Chinese communists have no right to intervene in matters concerning the waters east of Taiwan, whether they involve Taiwan's sovereignty or jurisdiction," he said.
China is a "trouble-maker that is damaging the status quo," Lin said.
Beijing recognizes no claims of sovereignty by Taiwan's government and has rejected multiple offers of talks by President Lai Ching-te, saying he is a "separatist."
