Chinese soldiers guard mosques in Urumqi
Some mosques in the western Chinese city of Urumqi have opened their doors to worshippers, in spite of an earlier order for them to stay closed.
At least two mosques opened after crowds gathered outside. It was not immediately clear if the authorities had sanctioned the move.
Urumqi, capital of the Xinjiang region, remains tense after days of ethnic violence that left 156 people dead.
Thousands of people are reportedly trying to leave the city.
The main bus station has seen 10,000 people go through its doors in recent days - double its normal traffic - an official there said.
Both Han Chinese and Muslim Uighurs are said to be fleeing the city, which still has a heavy security presence following the violence that began on Sunday.
Officials posted notices outside Urumqi's mosques, instructing people to stay at home to worship on Friday, the holiest day of the week in Islam.
One official told the Associated Press the decision was made "for the sake of public safety".
But hundreds of Uighurs defied the order and gathered outside at least two mosques in the city.
The BBC's Quentin Sommerville, outside one of the mosques, was told by one worshipper that they had insisted they be allowed in - and the gates were opened without any resistance or violence.
"We decided to open the mosque because so many people had gathered. We did not want an incident," a policeman outside the White Mosque in a Uighur neighbourhood told the Associated Press.
"I'm glad they are letting us in today," one worshipper, Ahmedadji, was quoted by the Reuters news agency as saying.
"There would have been a lot of unhappiness if they hadn't".
Meanwhile, the city's main bus station is reported to be heaving with people trying to escape the unrest.
Extra bus services have been laid on and touts are charging up to five times the normal face price for tickets, the AFP reports.
XINJIANG: ETHNIC UNREST
Main ethnic division: 45% Uighur, 40% Han Chinese
26 June: Mass factory brawl after dispute between Han Chinese and Uighurs in Guangdong, southern China, leaves two Uighurs dead
5 July: Uighur protest in Urumqi over the dispute turns violent, leaving 156 dead - most of them thought to be Han - and more than 1,000 hurt
7 July: Uighur women protest at arrests of menfolk. Han Chinese make armed counter-march
8 July: President Hu Jintao returns from G8 summit to tackle crisis
"It is just too risky to stay here. We are scared of the violence," a 23-year-old construction worker from central China said.
Many are university students, who have been told to leave the city earlier than they might have planned.
The violence began on Sunday when Uighurs rallied to protest against a deadly brawl between Uighurs and Han several weeks ago in a toy factory in southern Guangdong province.
Officials say 156 people - mostly Han - died in Sunday's violence.
Ethnic Han vigilante groups have been threatening to take revenge, leaving many Uighurs afraid to leave their homes.
The atmosphere remains tense, with troops in place across the city and armed police surrounding Uighur neighbourhoods, says our correspondent.
More than 1,400 people are thought to have been detained.
On Thursday, China said it had "a great deal of evidence" that some of those involved in the violence had "training from foreign terrorist groups including al-Qaeda".
Foreign ministry official Qin Gang did not say what the evidence was, but said the groups were "inextricably linked with three vicious forces from abroad".
Beijing has also accused US-based Uighur leader-in-exile Rebiya Kadeer of organising the disorder. She has denied the allegations.
Tensions have been growing in Xinjiang for many years, as Han migrants have poured into the region, where the Uighur minority is concentrated.
Many Uighurs feel economic growth has bypassed them and complain of discrimination and diminished opportunities.