A Chinese mainland spokesperson on Wednesday condemned a recent joint statement issued by Japan and the Philippines and their planned maritime delimitation negotiations involving waters east of Taiwan, describing the move as illegal and invalid.

Speaking at a regular press conference, Zhu Fenglian, spokeswoman for the State Council Taiwan Affairs Office, stated that the proposed maritime boundary between Japan and the Philippines covers waters east of China's Taiwan and that the planned delimitation talks seriously infringe upon China's maritime rights and interests.

"There is only one China in the world, and Taiwan is part of China," Zhu said. She asserted that the move constitutes a serious violation of international law and the basic norms governing international relations, and is therefore entirely illegal and without validity.

On May 28, following a meeting between Japanese Prime Minister Sanae Takaichi and visiting Philippine President Ferdinand Marcos Jr, Tokyo and Manila announced the launch of formal negotiations on the delimitation of their exclusive economic zones and continental shelves. According to the joint statement, the proposed delimitation areas include overlapping waters east of Taiwan.

Zhu called on people on both sides of the Taiwan Strait to jointly safeguard China's sovereignty and territorial integrity, as well as the overall interests of the Chinese nation. She warned that if the Democratic Progressive Party authorities in Taiwan seek support from external forces and act against the interests of the Chinese nation, they will face condemnation from compatriots on both sides of the Strait and be judged by history.

On Monday, the China Coast Guard conducted a law enforcement patrol in waters east of Taiwan in response to Japan and the Philippines unilaterally launching maritime delimitation talks in such waters, according to Jiang Lue, a spokesperson for the China Coast Guard.