A Chinese think tank has released a legal opinion condemning the decision of Japan and the Philippines to initiate maritime delimitation talks related to the waters east of China's Taiwan Island, saying that the move "constitutes an internationally wrongful act" because it bypasses China, which is a direct stakeholder.

The legal opinion, released by the Beijing-based China Institute for Marine Affairs under the Ministry of Natural Resources, said that Japan and the Philippines announced the talks without consultation with China and in disregard of the region's specific geographical circumstances. The move violates the principles of sovereign equality, good faith, cooperation and self-restraint under international law, it said.

The Chinese Foreign Ministry had condemned the move shortly after Japan and the Philippines announced the proposed talks on May 28 during Philippine President Ferdinand Marcos Jr's visit to Japan.

Ministry spokeswoman Mao Ning said the move severely violates China's maritime rights and interests and the United Nations Convention on the Law of the Sea, or UNCLOS. She added that China has lodged solemn representations with both countries.

Relevant Chinese authorities have voiced firm opposition to the proposed talks, with the China Coast Guard and other maritime bodies conducting patrols in waters east of Taiwan Island in recent days.