BEIJING - China slammed Japanese Prime Minister Taro Aso on Thursday for his offering to the Yasukuni shrine for war dead, warning of damage to ties while the two Asian powerhouses grapple with financial woes and North Korea.

Chinese Foreign Ministry spokeswoman Jiang Yu made no mention of calling off Aso's planned trip to Beijing next week, but she said his offering of a potted tree to the controversial Tokyo shrine strained relations between Asia's two biggest economies.

The Yasukuni shrine to millions of war dead -- including some convicted as criminals by a post-World War Two tribunal -- is seen by China and other Asian countries as a symbol of Japan's lack of contrition for bloodshed and atrocities in the 1930s and 1940s.

China has already used diplomatic channels to express its strong concern and dissatisfaction, and stressed the high sensitivity of historical issues, Jiang said in a statement read out on Chinese state television news.

Any erroneous actions by Japan will have gravely negative consequences for bilateral relations, and we demand that the Japanese side exercise caution in its words and actions and appropriately deal with this.

Asked at a later news conference about Aso's planned visit, Jiang was vague. Relevant information will be released in due course, she told reporters.

Even passing squalls between Beijing and Tokyo can ripple throughout the region.

Japan and China are the world's second and third biggest economies respectively, accounting for two-thirds of Asia's economy. They are also key players dealing with North Korea, which has raised tensions by firing a long-range rocket and saying it will abandon nuclear talks with regional powers.

Liu Jiangyong, an expert on China-Japan relations at Tsinghua University in Beijing, said the summit would probably go ahead, giving Aso and Chinese President Hu Jintao a chance to exchange views on the financial crisis and on North Korea.

I don't think this will lead to a rupture in high-level visits, but it will damage trust between the two sides at this very important time, said Liu, a former government aide.

REACTION HARDENS

Earlier this week, Jiang gave a milder reaction to the offering. When Shinzo Abe, then Japanese prime minister, made a similar tribute to the shrine in 2007, China did not issue a condemnation.

But Liu, the Tsinghua professor, said Beijing felt it had to speak out now because Aso is about to visit. China felt that Japan has been testing its bottom-line over the Yasukuni shrine issue, he said.

Beijing is sensitive to deep public distrust of Japan, which stoked sometimes violent protests in Chinese cities in 2005, and this year authorities are especially wary of unrest.

The Chinese public reaction to Aso's offering has reached nowhere near the pitch of that time. There have been no street protests. But Chinese-language internet sites have carried bitter denunciations of Japan.

The tendency of the Japanese right wing to stir up the dead remains clear, said one comment on the popular Sina.com.cn blog site. We must view China-Japan political and economic relations with a wary eye.

Japan's relations with China chilled during former Prime Minister Junichiro Koizumi's 2001-2006 time in office, in part because of his repeated visits to the shrine where Japanese wartime leaders are honored along with the nation's war dead.

Ties warmed after Koizumi left office, with the two subsequent prime ministers staying away from Yasukuni.

Nobody wants to go back to the Koizumi ice-age of Sino-Japanese ties, said Koichi Nakano, a political science professor at Sophia University in Tokyo.

China doesn't want to displease its public at a time of economic crisis and the Japanese side is courting a sort of 'religious right', but at the government level, it is unlikely to get out of hand this time, said Nakano.

Japanese Deputy Chief Cabinet Secretary Jun Matsumoto said Tokyo would promote good relations.

The government will continue to make efforts to promote comprehensively a mutually beneficial relationship based on common strategic interests as agreed by leaders of both countries, he told a news conference.

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