BEIJING, March 27 (Xinhua) -- A spokesman for the Taiwan Affairs Office of the State Council said on Wednesday that the mainland and Taiwan should set aside differences and jointly ward off threats from Japan to China's sovereignty over the Diaoyu Islands.

Yang Yi said at a regular press conference that the Diaoyu Islands and their affiliated islets are China's indisputable territory, so Chinese compatriots from both the mainland and Taiwan should safeguard Chinese sovereignty over these territories.

Yang added that protecting the rights and interests of fishermen from the mainland and Taiwan is the responsibility of both sides.

Tension has been high between China and Japan since last year, as the latter claims sovereignty over the Diaoyu Islands, despite them being China's inherent territory.

"Japan is solely responsible for the current issue over the Diaoyu Islands," said Yang. "The key to tackling it lies in Japan's attitude toward the reality."