China has lodged solemn representation and protest to Japan for violating its territorial sovereignty after two Japanese activists landed on its Diaoyu Islands, according to a Foreign Ministry spokesman on Friday.

Liu Weimin made the remarks at a routine press briefing when asked to comment on the incident.

Media reports said two Japanese right-wing activists went ashore on Beixiaodao, an islet of the Diaoyu Islands in the East China Sea on Thursday.

"The Diaoyu Islands and its affiliated islands have been China's inherent territory since ancient times," Liu reiterated, noting that the illegal actions of the activists gravely violated China's territorial sovereignty.