BEIJING, Dec. 23 -- China on Wednesday rejected comments made by Japan about its ship patrol near the Diaoyu Islands, saying the action was "irreproachable."

"The Chinese coastguard ship is equipped with what appeared to be four gun turrets," Japan's coastguard was quoted by Reuters as saying on Wednesday.

The Diaoyu Island and its adjacent islets have been part of Chinese territory since ancient times, Foreign Ministry spokesperson Hong Lei said at a regular news briefing.

"The patrol by the Chinese coastguard is beyond reproach," Hong said, adding that the equipment onboard the vessel is no different from international standards.