As ethnic tensions rise in China's Xinjiang province, the government is vowing to execute any rioters who commit crimes with "cruel means."
Thousands of security forces flooded Urumqi, the capital of Xinjiang province, Wednesday in an effort to quell the clashes that have already left 156 people dead.
Chinese President Hu Jintao also cut short his G8 visit to return home to help deal with the unrest.
The crisis began on Sunday between minority Uighurs and Han Chinese, which is the country's majority ethnic group. By the end of the day, 156 people had died in the fighting.
On Wednesday, Communist Party chief Li Zhi told a televised news conference that many people had been arrested, including students.
"To those who committed crimes with cruel means, we will execute them," he said.
Zhi also said government forces would crack down on any security risk but did not give further details.
In addition to the deaths, more than 1,100 people were wounded in Sunday's violence and hundreds of vehicles were damaged.
Many Uighurs say the riots were triggered by the June 25th deaths of Uighur factory workers in a brawl in the southern Chinese city of Shaoguan.
Although state-run media said two workers died, many Uighurs believe more actually died. The minority group says the incident reveals how little the government cares about them.
Wang, a Han Chinese man who would only give his surname, said the government has been telling them not to get involved in any kind of violence.
"They've been broadcasting this on the radio, and they even drove through neighbourhoods with speakers telling people not to carry weapons," he told The Associated Press.
Helicopters also dropped leaflets urging the 2.3 million Urumqi residents to remain calm.
The leaflets included a message from Xinjiang's Communist Party secretary urging everybody "to return home, return to their work units and return to their communities."
Despite the warnings, the state-run Xinhua News Agency said there were still some minor clashes and "sporadic standoffs" between protesters and security forces.
According to the BBC, thousands of paramilitary police have stormed the city in a situation that is "virtually martial law."
Most of the police had shields and clubs but some had assault rifles with bayonets.
Mamet, a Uighur businessman who would give only part of his name, said he didn't believe the government.
"They need to tell the Han to retreat. We're going to stay here to protect our homes," he said.
With files from The Associated Press
