Relations between China and Japan have undergone "historic change", China's vice foreign minister said Thursday, a day after the two sides partly resolved a long-running spat on gas fields.

"Speaking about China-Japan relations, particularly after President Hu Jintao's visit, a sea change has taken place, historic change, in my view," Wu Dawei told reporters.

Speaking a day after China and Japan announced they would jointly develop some gas fields in the East China Sea, partly resolving a dispute between the two, Wu said relations were at a "new starting point."

The traditional rivals have recently been working to repair relations which have long been tense due in part to the legacy of Japanese imperialism.

Hu even paid a landmark visit to Japan last month -- only the second by a Chinese head of state to Japan.

But Wu warned there were still areas of dispute in which China's position remained unchanged, including the thorny issue of the Diaoyu islands in the East China Sea, currently controlled by Japan but also claimed by China.

"We should not rush to settle the issue because if we rush to a resolution, either by Japan or China, then there will only be one possible solution, that is a non-peaceful solution," Wu said.

In a further sign that the Diaoyu islands remained a controversial issue, Chinese nationalists demonstrated Wednesday outside the Japanese embassy in Beijing, urging Japan to "get out of the Diaoyu islands."

The protest suggested public opinion might not be in line with government efforts to patch up ties with Japan, but Wu said the Chinese people supported friendship with Tokyo.

"I'm confident that we can surely reach the goal of having our people living together in friendship for generations to come."