In Istanbul, Turkish protesters burned the Chinese flag at a rally
Turkey's prime minister has described ethnic violence in China's Xinjiang region as "a kind of genocide".
"There is no other way of commenting on this event," Recep Tayyip Erdogan said.
He spoke after a night-time curfew was reimposed in Xinjiang's capital, Urumqi, where Muslim Uighurs and Han Chinese clashed last Sunday.
The death toll from the violence there has now risen from 156 to 184, China's state-run Xinhua news agency reports. More than 1,000 people were injured.
Turkey is secular but the population is predominantly Muslim and it shares linguistic and religious links with the Uighurs in China's western-most region.
Quentin Sommerville, BBC News, Urumqi
After Friday's prayers, a small group of Uighur Muslims marched along an Urumqi street demanding the release of men detained for their alleged role in last Sunday's riot.
A large number of riot police surrounded the group, they punched and kicked the protestors - one officer used his baton to beat one of the Uighurs. A number of foreign journalists had their equipment seized, some have been detained.
Earlier the group said they feared for their safety. There's no word from the authorities as to what happened to them.
"The event taking place in China is a kind of genocide," Mr Erdogan told reporters in Turkey's capital, Ankara.
"There are atrocities there, hundreds of people have been killed and 1,000 hurt. We have difficulty understanding how China's leadership can remain a spectator in the face of these events."
The Turkish premier also urged Beijing to "address the question of human rights and do what is necessary to prosecute the guilty".
Mr Erdogan's comments came a day after Turkish Trade and Industry Minister Nihat Ergun urged Turks to boycott Chinese goods.
Beijing has so far not publicly commented on Mr Erdogan's criticism.
But it said that of the 184 people who died, 137 were Han Chinese.
Earlier on Friday, the Chinese authorities reimposed a night-time curfew in Urumqi.
The curfew had been suspended for two days after officials said they had the city under control.
Mosques in the city were ordered to remain closed on Friday and notices were posted instructing people to stay at home to worship.
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
But at least two opened after crowds of Uighurs gathered outside and demanded to be allowed in to pray on the holiest day of the week in Islam.
"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 AP news agency.
After the prayers, riot police punched and kicked a small group of Uighurs protesters, who demanded the release of men detained after last Sunday's violence, the BBC's Quentin Sommerville says.
Meanwhile, the city's main bus station was reported to be crowded with people trying to escape the unrest.
Extra bus services had been laid on and touts were charging up to five times the normal face price for tickets, AFP news agency said.
"It is just too risky to stay here. We are scared of the violence," a 23-year-old construction worker from central China said.
The violence began on Sunday when a Uighur rally to protest against a deadly brawl between Uighurs and Han Chinese several weeks ago in a toy factory in southern Guangdong province turned violent.
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.
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