BEIJING China expressed serious concern on Wednesday after Japan and Taiwan signed a fishing agreement for the seas around a disputed group of East China Sea islands which have been at the center of an increasingly hostile stand-off between Beijing and Tokyo.
"We are extremely concerned about Japan and Taiwan discussing and signing a fishing agreement," Foreign Ministry spokesman Hong Lei told a daily news briefing.
"We hope that Japan earnestly abide by its promises on the Taiwan issue and act cautiously and appropriately," he said.
Japan has diplomatic ties only with China and recognizes Taiwan as belonging to China, but it maintains close economic and cultural relations with Taiwan.
China and Taiwan have been ruled separately since defeated Nationalist forces fled to the island at the end of a civil war with the Communists in 1949. China has never renounced the use of force to bring Taiwan under its control.
While China is generally happy for Taiwan to sign trade and business agreements with other countries, it looks askance at any deals that suggest Taiwan is a sovereign country.
Japan agreed with Taiwan to let Taiwanese fishing boats operate in part of Japan's exclusive economic zone around the islets that are controlled by Japan, but also claimed by China and Taiwan.
The waters around the islands, called the Senkaku in Japan and Diaoyu in China, are rich fishing grounds and have potentially huge oil and gas reserves.
The dispute has escalated in recent months to the point where China and Japan have scrambled fighter jets while patrol ships shadow each other, raising fear that an unintended incident could lead to a broader clash.
Ties between Beijing and Taiwan, meanwhile, have warned rapidly since the China-friendly Ma Ying-jeou was elected the island's president in 2008.
(Reporting by Ben Blanchard; Additional reporting by Kiyoshi Takenaka in TOKYO; Editing by Robert Birsel)