Police have fired tear gas to try to restore order as hundreds of Han Chinese armed with clubs marched through the Xinjiang capital of Urumqi, smashing shops and knocking over food stalls run by Muslims.
The city, where rioting and ethnic clashes killed 156 people two days ago, was extremely tense, with security officials breaking up a separate protest near the railway station.
Muslim women faced off with armed Chinese police, wailing for the release of their sons and husbands detained after the riots.
Police used loudspeakers to appeal to the Han Chinese crowd to stop, but a group of about 300 protesters were joined by two other columns of marchers on Jiefang Nan Road. They appeared to be heading for the Grand Bazaar, the predominantly Muslim area of the city, but were blocked by police.
The crowd, which took up several blocks of the five-lane road, chanted "Unite" and "Modern Society", and waved wooden sticks, lead pipes, shovels and hoes in the air.
As they headed down a back street toward a mosque, several loud explosions rang out followed by rising white puffs of smoke - and then the smell of tear gas.
The Han Chinese march follows a protest by about 200 people, mostly women from the Uighur minority group, who protested against the security crackdown which has led to more than 1,000 arrests in Urumqi following Sunday's riot, the area's worst ethnic violence in decades.
The women said police went through their neighbourhood on Monday night and strip-searched men to check for cuts and other signs of fighting before hauling them away.
A woman said about 300 people were arrested in the market in the southern section of town.
The protesters briefly scuffled with paramilitary police, who pushed them back with long sticks before both sides retreated. The 90-minute protest played out in front of foreign reporters on a government-guided tour.
