The Zhengzhou detachment will mainly deal with terrorism, violent crimes, riots and threats to public security, and will also be responsible for safety during major public occasions, the state news agency Xinhua said.

There have been two major disturbances near Zhengzhou in the last year.

A violent clash over a land dispute injured about 30 people last August, and there were several fatalities during clashes between Han Chinese and Muslims three months later.

Some 74,000 protests and riots broke out across China last year, involving more than 3.7 million people, Reuters quoted Chinese Security Minister Zhou Yongkang as saying.

The government, fearful as ever of any instability getting out of control, is now putting in place a range of measures to deal with the surge in demonstrations, says BBC East Asia editor Clare Harkey.

They include new rules on complaining to the authorities - citizens are now banned from petitioning central government directly.