Japan is unlikely to invite South Korea to an October naval fleet review amid strained relations between the two countries over trade and other issues.

Japan's Nikkei daily on Sunday quoted a senior Japanese defense official as saying that it's "very hard" to invite South Korea under the circumstances.

The official reportedly said that last year's military radar dispute and Seoul's recent decision to end a military intel-sharing deal with Japan are inconducive to bilateral defense cooperation. 

The official added that exchange programs set for late August between Japan's self-defense force and South Korea's Army were suspended at Seoul's request. 

Japan's self-defense force reportedly plans to send invitations to the United States, Australia, India and China for the October 14 fleet review in Sagami Bay, near Tokyo.

Japan holds such a review every three to four years. The last was held in October 2015, with South Korea’s Daejoyeong destroyer present at the event.