URUMQI (China) - HAN Chinese armed with iron bars and machetes roamed Urumqi city on Tuesday looking to wreak revenge on Uighurs for bloody ethnic clashes two days earlier which killed 156 and wounded more than 1,000.

Outnumbered riot police used tear gas to try to disperse the thousands of angry protesters who flooded the capital of the northwestern region of Xinjiang.

In a sign of government anxiety about the unrest, the city's Communist Party boss Li Zhi took to the streets to plead with protesters to return home, and overnight 'traffic restrictions' - originally announced as a curfew - came into effect to halt the violence, in which many people were injured.

Security forces intervened to stop fighting, breaking up a battle between hundreds of rock-throwing Han and Uighurs and forcing a Han mob to leave a building they stormed in a Uighur area, a Reuters reporter said. There were no reports of deaths.

But riot police stood warily by as crowds vented their anger by throwing rocks at a mosque and smashing restaurants and shops owned by Uighurs, a Turkic people who are largely Muslim and share linguistic and cultural bonds with Central Asia.

'They attacked us. Now it's our turn to attack them,' a Han man in the crowd told reporters. He refused to give his name.

The crowd were carrying an improvised arsenal of meat cleavers, metal rods and spades seized from building sites, rocks and wooden clubs, and the most extreme shouted 'kill them' and 'exterminate the Uighurs.'

Rioters said they wanted revenge for violence on Sunday. Beijing has not given a breakdown of the ethnicity of the dead, but official media reports initially focused on Han victims and Urumqi's Han community seem sure they were the main targets in the country's worst unrest for years.

'We're here to demand security for ourselves,' said another protester who would not give his name.

By evening the club-wielding mobs had melted away. As curfew came down police moved through emptying streets telling people to go home and handing out leaflets with a speech by a top regional official, Wang Lequan, calling for peace.

Xinjiang has long been a hotbed of ethnic tensions, fostered by a yawning economic gap between Uighurs and Han Chinese, government controls on religion and culture and an influx of Han Chinese migrants who are now in the majority in most key cities. -- REUTERS