Uighurs pray in a mosque in Urumqi in China on Friday. (Kyodo News/Associated Press)

Crowds of Uighurs forced their way into prayers on Friday, defying government orders that mosques in areas affected by ethnic violence this week in China's Xinjiang province be closed early.

Hundreds of men gathered at White Mosque in Urumqi's Uighur neighbourhood of Er Dao Qiao ahead of prayers in the capital, and demanded they be allowed inside.

Eyewitness reports put the gathering at between 400 and 1,000 worshippers.

Chinese police special forces and a truck load of paramilitary police patrol the area near the Great Bazaar where a small group of Uighur protested in Urumqi on Friday. (Ng Han Guan/Associated Press)"We decided to open the mosque because so many people had gathered. We did not want an incident," an unnamed police officer told The Associated Press.

At the Yang Hang mosque, worshippers removed a white notice glued to the front gate indicating the closure and hundreds of men streamed inside clutching prayer mats.

About 40 Uighurs also began a march in the area that was quickly blocked off by police.

There were reports of minor confrontations stopped by police as people left prayers at the mosques. Eyewitness reports indicated several people were detained.

Many of the mosques in Urumqi are in the area where ethnic fighting broke out earlier this week between Han Chinese and minority Muslim Uighurs.

Officials have said at least 156 died on Sunday, and more than 1,000 have been injured and 1,400 detained.

'No reason to shut the gate'

Officials at some mosques in the city said they had been ordered closed for public safety reasons. Reports indicated only mosques in the areas affected by the violence fell under the order.

"There was no reason to shut the gate. They said it was for our safety but actually there is no need — nothing will happen here," a man only identified as Kaishar told The Associated Press.

A cluster of people outside the Dong Kuruk Bridge Mosque told reporters they were frustrated that their mosque remained closed.

"We feel we are being insulted. This is our mosque," a man told Reuters.

The government has imposed curfews in the city and flooded the streets with security forces in an effort to end the street battles.

The protests started in Urumqi, when demonstrators gathered to demand justice for two Uighurs killed in June during a fight with their Han co-workers at a factory in southern China.

Hundreds of vehicles, stores and street vendor stalls were also damaged or set ablaze during the protests, officials said.

The Uighurs, an ethnically Turkic, predominantly Muslim group, make up the majority in Xinjiang.

Their relations have often been tense with the ethnic Han Chinese who predominate in the country. Many Uighurs feel they're discriminated against by the government in Beijing and a Uighur separatist movement has existed for decades.

With files from The Associated Press