A five-day air combat exercise by Japan's Self-Defense Forces and United States troops based in Japan has ended, as the two ally countries prepare for deliberations to revise their security cooperation treaty.

The drill was conducted over Pacific waters on Tuesday off the coast of Shikoku, the fourth-largest of Japan's islands, with four F-4 fighter jets and an unspecified number of personnel from JASDF and six FA-18 fighters and some 90 soldiers from the US, according to Japan's NHK.

Foreign affairs and defense officials from the two countries are scheduled to begin discussions on a revision to the guidelines for their defense cooperation on Thursday.