The Philippines has firmly rejected China’s claim of sovereign rights over waters near Batanes, its northernmost province.

The Department of Foreign Affairs said on Friday that the Chinese research vessel Jia Hai Ke 7 was detected about 37 nautical miles northwest of Itbayat, Batanes, well within the Philippines’ 200-nautical-mile exclusive economic zone.

The department said the Philippine Coast Guard was conducting lawful operations in response to suspected unauthorised marine scientific research. Under the UN Convention on the Law of the Sea, such research in a coastal state’s zone requires its consent, which Manila said was never sought or given.

The Chinese embassy in Manila said the vessel was conducting normal operations in waters under China’s jurisdiction and accused the coast guard of harassment.

The dispute extends the maritime row beyond the traditional flashpoints in the West Philippine Sea, with Beijing citing overlapping claims and Manila urging it to respect international law.