China Tuesday slammed some Japanese lawmakers' aerial inspection of the Diaoyu Islands.

"The Diaoyu islands and its adjacent islets have been Chinese territory since ancient times," Chinese Foreign Ministry spokesman Ma Zhaoxu said at a regular press briefing when responding to a question.

Media reports said four Japanese lawmakers, including former cabinet member Kazuhiro Haraguchi, inspected the Diaoyu Islands from the air on a chartered plane on Oct. 9.

Some people in Japan are attempting to undermine China's territorial sovereignty and China-Japan relations with an illegal aerial inspection, which is a move doomed to failure, Ma said.

China has made clear to Japan its solemn stance concerning the lawmakers' actions, he added.

China believes the two countries should properly handle the relevant sensitive issue through talks and consultation in line with the spirit of the four political documents the two countries have signed, within the framework of a mutually beneficial and strategic bilateral relationship.

Promoting improvement and development of China-Japan relations is in the fundamental interest of both nations, Ma said.