Since then Chinese ships have been sailing in and out of what Japan says are its territorial waters around the islands, prompting warnings from Tokyo.

BBC: Japan seeks to boost military spending

Chinese government ships have been sailing in and out of what Japan says are its territorial waters around the islands, and in recent weeks Japanese fighters have been scrambled on a number of occasions after what Japan called an airspace violation by a Chinese government plane late last year.

BBC: Japan PM Shinzo Abe begins South East Asia push in Vietnam

Chinese ships have also been sailing in and out of what Japan says are its territorial waters around the islands in recent months.

BBC: Japan PM Abe: China handling of islands row 'wrong'