Japan has asked China to prevent flying objects from entering Japanese airspace again.

Senior Japanese defense officials made the request to their Chinese counterparts at a meeting in Tokyo on Tuesday. Suspected Chinese spy balloons have been spotted in Japan's airspace in the past.

The Japanese side said unauthorized entry into the country's airspace must not be tolerated.

The two sides agreed that they will continue working to start operations of defense hotlines in coming months.

The hotlines are designed to prevent accidental clashes between Japan's Self-Defense Forces and the Chinese military.

Also on Tuesday, senior diplomats from the two countries held a meeting.

The Japanese side conveyed its grave concern about the situation in the East China Sea, which includes the Senkaku Islands.

The two sides reaffirmed that they will keep in close communication to build constructive and stable relations.

Japan controls the islands. China and Taiwan claim them. The Japanese government maintains the islands are an inherent part of Japan's territory, in terms of history and international law. It says there is no issue of sovereignty to be resolved over them.

The meetings of defense and foreign affairs officials were held before their first Japan-China Security Dialogue in four years on Wednesday.