Beijing (AsiaNews/Agencies) – Thousands of people marched today in Shanghai shouting slogans against Japan's wartime atrocities, throwing rocks and bottles at Japanese restaurants, breaking windows on their way to and at the Japanese consulate where they also burnt Japanese flags.

Similarly, about 10,000 demonstrated in Hangzhou and another 2,000 in Tianjin, near Beijing.

In the capital but also in Guangzhou and Chongqing, thousands of police officers in full anti-riot gear were out patrolling the streets to prevent acts of violence.

The movement seems to be building up steam thanks to the internet where messages are being posted on anti-Japan internet forums offering clear instructions as to how to participate.

The latest call is for Chinese to demonstrate in front of the Japanese Embassy in Beijing during tomorrow's visit by Japan's Foreign Minister Nobutaka Machimura.

However, little information is available on the identity of organisers of this virtual grapevine. No prominent anti-Japan group involved in previous rallies has claimed a role in the plans or protests for this weekend.

Some analysts suggest that the protests might even be linked to government insiders.

Protests began after the media revealed that Japanese schools would adopt textbooks that glossed over Japan's atrocities during the Second World War.

This came after Sino-Japanese relations grew tenser for months over Japan's application for permanent membership on the Security Council of the United Nations as well as clashes in the energy field.

A few months ago Russia went with a Japanese bid to build an oil pipeline from its Siberian oilfields.

More recently, Japan's decision to award exploration rights in a contested gas field in the East China Sea that China claims has further poisoned relations.

Still, both parties do not intend to undermine their trade relations which have topped US$ 178 billion per year.

In an attempt to defuse the situation, Japanese Prime Minister Junichiro Koizumi said more protests in China wouldn't be a bad thing if they were non-violent and orderly.

Furthermore, Japan's annual report on diplomacy said that "[s]table Japan-China relations are indispensable for the peace and prosperity in the Asia-Pacific region".