Police are said to have fired warning shots before they killed the men
Two ethnic Uighurs have been shot dead by police in Urumqi, capital of China's Xinjiang province, officials have said.
A government statement announced that a third "lawbreaker" had been injured in the incident.
The police were trying to prevent the three men attacking another Uighur, the government officials said.
The violence comes after authorities said calm had been restored to Urumqi, after at least 180 people were killed in rioting last week.
Thousands of extra security personnel have been patrolling the city since the violence erupted on 5 July.
The police spotted the three Uighurs chasing a fourth near a city centre hospital, according to official reports. They were carrying long knives and clubs.
Local officials say police officers tried to stop the suspects attacking their victim, but the Uighurs resisted.
There is a heavy security presence in Urumqi after last week's unrest
The police were said to have fired warning shots, but these were ignored. They then fired at the men, killing two of them.
The other is being treated in hospital along with the victim of the assault, a government statement said.
Initial reports from a journalist for Hong Kong radio suggested two policemen had also been shot in the confrontation, but these reports have not been substantiated.
The violence in Xinjiang began on 5 July during a protest by Uighurs over a brawl in southern China in late June in which two people were killed.
Chinese officials have said 184 people are known to have been killed in the violence in Urumqi, and 1,680 injured.
The officials said 137 were Han Chinese, 46 were from the indigenous Uighur community and one was an ethnic Hui, the officials said.
Uighur groups in exile have said hundreds of Uighurs were killed.
In a televised speech on Monday, Xinjiang governor Nuer Baikeli said: "We will firmly protect the dignity of the law, and make all efforts to track down the violent criminals who took part in the beating, smashing, looting and burning."
He warned that those found guilty would be punished "with the utmost severity".