Japan, China and South Korea have failed for the third straight year to hold an annual summit, despite an agreement that their leaders gather for talks every year.

Among the factors behind the trilateral dialogue framework's effective breakdown are soured Tokyo-Seoul ties over a long-standing wartime labor issue and Beijing's intensifying military activities in the East China Sea, government sources said.

The last meeting of leaders from the three East Asian nations was held in December 2019 in the southwestern Chinese city of Chengdu.