The squads are to be stationed in 36 cities, but the largest deployments are in Beijing and Shanghai as the Communist Party asserts its hold on power and gears up for the 2008 Olympic Games.

The latest team was inaugurated this week in the city of Zhengzhou, in central Henan province, China’s most heavily populated, with more than a hundred million people. More people sue the Government in Henan than in any other region.

People are becoming bolder in voicing their grievances in a society in which economic liberalisation has created a yawning gap between urban rich and rural poor, and under an authoritarian system that offers numerous opportunities for officials to get rich through corruption.

Officials said that the squads of 600 men had undergone training to battle terrorism, crush riots and respond to other emergencies. The men, the elite of the police force, have acquired skills such as survival techniques and fighting in hostile environments.

In recent years, popular protests have surged in China over disputes ranging from land rights to pensions, the environment and corruption. Several disturbances have turned violent when local governments have ordered in police or armed men. Zhou Yongkang, the Public Security Minister, said recently that the number of mass protests across China soared to more than 74,000 last year, with 3.76 million people taking part, up from 10,000 incidents a decade ago.

The authorities are particularly keen to avoid trouble during the Games, a showpiece that is seen as a coming-out party for an emerging superpower. In the 1990s sporadic bombings in the capital were blamed on members of the Muslim Uighur minority from the far western Xinjiang region that borders the Central Asian states of Kazakhstan, Kyrgyzstan and Tajikistan. Several particularly violent riots have broken out in Xinjiang among Uighurs demanding an independent state of East Turkestan.

The task of suppressing unrest in China has traditionally been assigned to the million-strong People’s Armed Police, a paramilitary force set up in 1983 to relieve the military of responsibility for internal security.

Acknowledging the problem of rising unrest, a vice-minister said last month that violent demonstrations were inevitable, given economic changes, and said that they were a sign of growing democracy.

Zhou Xiaozhen, a professor of sociology at People’s University in Beijing, questioned the use of force. He said: “I believe that when you save a plant, you should save the plant, not the leaves and the trunk. I question whether this way the Government can even cure the leaves.”

He urged greater attention to narrowing the gulf between rich and poor rather than deploying expensive armoured cars. He said: “The gap between rich and poor, urban and rural, is widening and this provides the earth for crimes to grow from. The illness should be cured from the roots.”

This week the Government ordered courts to stop hearing cases over land disputes and forcible demolition brought by disgruntled victims of eviction. Litigants will be referred to relevant government departments for arbitration and only if property owners are still unhappy will they be allowed to file a lawsuit. Demolitions do not have to stop during litigation if compensation or relocation has been offered to occupants.