Major world powers should abide by the terms of the Cairo Declaration, issued in 1943, in order to avoid confrontations in East Asia, observers said as they mark the 70th anniversary of the signing of the document.

The Cairo Declaration played a key role in charting international politics after World War II.

While urging Japan to obey the rules established by successive post-World War II documents, analysts also called on Washington to be consistent in its approach to building the world order in the postwar period and avoid pushing Japan into deeper regional confrontation.

On Dec 1, 1943, China, the United States and Britain issued the Cairo Declaration.

They agreed that "Japan shall be stripped of all the islands in the Pacific" it had seized or occupied since the beginning of World War I and "all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa (Taiwan) and the Pescadores, shall be restored to the Republic of China".

The declaration also demanded Japan "be expelled from all other territories which she has taken by violence and greed".

It confirmed China's sovereignty over those territories stolen by Japan, including the Diaoyu Islands.

"The Japanese must comply with the Cairo Declaration, which is the fundamental source of a series of international laws," said Liu Jiangyong, deputy dean of the Institute of Modern International Relations at Tsinghua University.

Hu Dekun, head of the Institute for International Studies at Wuhan University, said the agreements made in a series of conferences in Cairo, Potsdam, Teheran and Yalta formed a complete legal system for postwar international relations.

"The Cairo Declaration and the Potsdam Proclamation represent the Allied powers' punishment of defeated Japan. And these documents also contributed to Japan's peaceful development in the postwar era," Hu said, adding that China sees the Cairo Declaration as representative of victory in World War II.

"The Cairo Declaration served as the basic document of setting up the postwar world order. And it is wrong for Japan to weaken the document's significance by questioning its validity."

While major world powers have defended and practiced the spirit of the declaration, the Japanese government is turning a blind eye to it by claiming that the Diaoyu Islands are Japanese territory.

Japan is diluting the importance of the declaration because it refuses to acknowledge its defeat in World War II and chooses to present a challenge to the status quo in the region, observers said.

Gao Hong, a Japanese studies professor at the Chinese Academy of Social Sciences, said that Japan's doubts on the legal implications of the declaration are groundless.

"From the point of view of the source of law, the Potsdam Proclamation was the successor of the Cairo Declaration, as it explicitly stated in Article 8 that 'the terms of the Cairo Declaration shall be carried out'," said Gao.

Later in September 1945, the Japanese government accepted the Potsdam Proclamation in explicit terms with the Japanese Instrument of Surrender and pledged to faithfully fulfill the obligations in the provisions of the proclamation. "Obviously, Article 8 must be included in the provisions of the Potsdam Proclamation," Gao noted.

Liu said the Cairo Declaration was also closely related to the normalization of ties between China and Japan in 1972.

"In the China-Japan Joint Statement, Japan affirmed that the government should fully understand and respect the position of the Chinese government and stick to the position of Article 8 in the Potsdam Proclamation," he said.

Observers said the Cairo Declaration was the consensus reached by the three powers and opinions of other countries must have been considered as well.

Mo Jingxi and Li Xiaofei contributed to this story.