TEHRAN - China's top legislator Wu Bangguo said here Monday that Japan's decision to "buy" the Diaoyu Islands is illegal and invalid.

Wu, chairman of the Standing Committee of the National People's Congress, briefed Iranian parliament speaker Ali Larijani on the latest development concerning the Diaoyu Islands.

The islands have been inherent territories of China since ancient times and China's position on the issue has been consistent and clear, Wu told Larijani.

Any forms of "buying the islands" by the Japanese side is illegal and invalid. China is firmly opposed to such moves, he said.

The determination the Chinese government and people on safeguarding sovereignty and territorial integrity is unswerving, Wu said.

With regard to China-Iran relations, Wu said their healthy development has not only brought tangible benefits to the two countries and peoples, but also made positive contributions to regional peace, stability and development.

China respects the development path, domestic and foreign policies Iran has chosen in accordance with its national conditions, said Wu.

Developing mutually beneficial and friendly cooperation with Iran on the basis of the Five Principles of Peaceful Co-existence is an important part of China's independent and peaceful foreign policy, he said. This policy will not change with changing international and regional situations, he said.

On the two countries' parliamentary exchanges, Wu said China's National People's Congress and the Iranian parliament have conducted friendly communication and therefore have laid down a relatively sound basis of cooperation.

The exchanges play an irreplaceable role in enhancing mutual understanding and friendship between the two peoples and boosting bilateral ties, Wu added.

Wu, who is on a four-nation tour, arrived here Sunday for a four-day visit. He will also visit Myanmar, Sri Lanka and Fiji.