Tokyo’s coastguard said it had spotted Chinese vessels near the Diaoyu Islands on 216 consecutive days, beating last year’s record

On Sunday, Japan said it observed four Chinese coastguard vessels sailing in the “contiguous” zone, referring to a 12-nautical-mile (22km) band that extends beyond Japan’s territorial waters.

Japanese officials regularly protest against the presence of the Chinese coastguard and other vessels in the waters surrounding the disputed islands.

Relations between Japan and China were strained by Tokyo’s decision to “nationalise” some of the islands in 2012.

On Friday, Japan’s coastguard and its US and Philippine counterparts staged joint training drills off Japan’s southwest shore – the second time the countries’ coastguards have held training drills together, and the first in Japan.