Japan has sounded out China about a plan to send a close aide of Prime Minister Shinzo Abe to Beijing in May to lay the groundwork for a summit between with Chinese President Xi Jinping later this year, Japanese and Chinese diplomatic sources said.

China did not respond but said it will keep a close watch on Japan's approach to the multinational territorial rows in the South China Sea, the sources told Kyodo News on Wednesday.

Foreign Minister Fumio Kishida plans to brief his Chinese counterpart, Wang Yi, on Tokyo's stance on the issue during a meeting in Beijing on Saturday. He will also try to reaffirm China's stance on cooperation for responses to global economic uncertainties, a step Tokyo hopes will help improve bilateral relations.