Hundreds of Uighur clashed with anti-riot police in the capital of China's Muslim region of Xinjiang on Tuesday, two days after ethnic unrest left 156 dead and more than 800 injured.

The protesters said their family members had been arbitrarily arrested in a crackdown after rioting broke out in the regional capital Urumqi on Sunday, a Reuters reporter said. Protesters vowed to keep up their definance.

'My husband was taken away yesterday by police. They didn't say why. They just took him away,' a woman who identified herself as Maliya told Reuters.

Fighting broke out when Uighur protesters advanced towards hundreds of anti-riot police carrying clubs and shields.

Abdul Ali, a Uighur man in his 20s who had taken off his shirt, held up his clenched fist. 'They've been arresting us for no reason, and it's time for us to fight back,' he said. Ali said three of his brothers as well as a sister had been among 1,434 suspects taken into police custody for questioning.

Local residents complained police were making indiscriminate sweeps of Uighur areas.

The crowd later started to thin out as the anti-riot police slowly retreated down the street on the outskirts of Urumqi.

Earlier on Tuesday, Xinjiang's Communist Party boss Wang Lequan said Sunday's unrest had been quelled, although he warned 'this struggle is far from over'.

Xinjiang's state-run media quoted Wang as calling for officials to launch 'a struggle against separatism'. Some Xinjiang newspapers also carried graphic pictures of the violence, including corpses, at least one of which showed a woman whose throat had been slashed.

Despite heightened security, some unrest appeared to be spreading in the volatile region, where long-standing ethnic tensions periodically erupt into bloodshed.

Police dispersed around 200 people at the Id Kah mosque in the Silk Road city of Kashgar on Monday evening, Xinhua said.

The report did not say if police used force but said checkpoints had been set up at crossroads between Kashgar airport and downtown. Kashgar is in the far west of Xinjiang.

Human Rights Watch's Asia advocacy director, Sophie Richardson, called for an independent probe into the unrest.

'Whoever started the violence, lowering ethnic tensions in the region requires the government to constructively address Uighur's grievances, not exacerbate them,' she said.

Along with Tibet, Xinjiang is one of the most politically sensitive regions in China and in both places the government has sought to maintain its grip by controlling religious and cultural life while promising economic growth and prosperity.

But minorities have long complained that Han Chinese reap most of the benefits from official investment and subsidies, making locals feel like outsiders.

Almost half of Xinjiang's 20 million people are Uighurs, while the population of Urumqi, which lies around 3,300 km (2,000 miles) west of Beijing, is mostly Han Chinese.

Chinese officials have already blamed the unrest on separatist groups abroad, who it says want to create an independent homeland for the Muslim Uighur minority.

Exiled Uighur businesswoman and activist Rebiya Kadeer, blamed by Chinese state media for being behind the violence, denied having anything to do with it. 'These accusations are completely false,' Kadeer said through an interpreter in Washington, where she now lives. -Reuters