China's top diplomat is likely to visit Japan later this month and possibly meet with Prime Minister Shinzo Abe to lay the groundwork for an upcoming trilateral summit of Japan, China and South Korea, government sources said.

State Councilor Yang Jiechi is also expected to meet Shotaro Yachi, a senior national security adviser to Abe, during a visit envisioned for the third week of October, the sources said Saturday.

Abe, Chinese Premier Li Keqiang and South Korean President Park Geun-hye are planning to hold a trilateral summit in Seoul later this month, with a bilateral meeting between Abe and Li expected to take place on the sidelines.

Also on the agenda for the meeting between Abe and Yang would be a discussion on holding meetings between Abe and Chinese President Xi Jinping on the sidelines of future international conferences, such as the Asia-Pacific Economic Cooperation forum summit in the Philippines in November, the sources said.

In the meeting with Yachi, the top Chinese diplomat may discuss how to promote three-way free trade among Japan, China and South Korea in a bid to secure a deal similar to the massive Trans-Pacific Partnership agreement reached earlier this month involving 12 Pacific Rim countries, they said.

Japan was a part of that deal but China and South Korea were not.

The sources said they see Yang's visit, which will be his first since he assumed his post in 2013, as evidence of Xi's intention to improve bilateral ties with Japan.

Yachi invited Yang to visit Japan when they met in Beijing in July.

Last November, the two issued a four-point agreement on improving bilateral relations, which led to the first summit between Abe and Xi since they came to power two years prior, later that month in Beijing.