URUMQI (China) - THOUSANDS of angry Han Chinese armed with poles, meat cleavers and other makeshift weapons stormed through Urumqi on Tuesday as the flashpoint city riven by ethnic tensions descended into chaos.

Heavily armed security forces fired tear gas at the crowds and ordered a night curfew in an effort to restore calm in Urumqi, capital of China's remote north-west Xinjiang region, where 156 people died in weekend clashes.

But tensions remained at boiling point, with Han Chinese roaming the city wielding machetes, bricks, chains, steel bars and other weapons while calling for revenge against Muslim Uighurs who they blamed for Sunday's carnage.

'The Uighurs came to our area to smash things, now we are going to their area to beat them,' one protester, who was carrying a metal pipe, told AFP.

World leaders have urged restraint from protesters and the authorities to prevent further violence.

'I urge Uighur and Han civic leaders and the Chinese authorities at all levels to exercise great restraint so as not to spark further violence and loss of life,' said Navi Pillay, the UN's top human rights official.

White House spokesman Robert Gibbs on Monday said the United States was 'deeply concerned' about the reports of deaths in Urumqi and called for 'all in Xinjiang to exercise restraint'.

US House Speaker Nancy Pelosi on Tuesday blamed China's 'harsh policies' for fuelling resentment among the Uighurs and urged Beijing to seek a dialogue with the Muslim minority.

Sunday's unrest, which also left more than 1,000 people injured, began with protests by Xinjiang's Uighurs, who have long complained of repression under Han Chinese rule.

Chinese authorities have blamed exiled Muslim Uighurs for masterminding the unrest - charges they deny - and announced on Tuesday they had arrested 1,434 suspects for murder, assault, looting and other crimes linked to the violence.

But Han Chinese in Urumqi declared they were not satisfied with the government response.

'It is time we looked after ourselves instead of waiting for the government,' said Dong Sun, a 19-year-old leader of one mob. -- AFP