Below is an article published by Radio Free Asia:

Uyghur petitioners from China's northwestern Xinjiang region face another obstacle in their bid to raise problems with the Chinese authorities in Beijing—they are now disallowed from traveling in public buses in the Chinese capital, according to a "secret" notice.

A bus driver stopped his packed vehicle during peak hour traffic along a highway in Beijing on Friday [20 April 2012] when he learned that three of his passengers were Uyghur petitioners, and summoned the police in what the petitioners called ethnic discrimination.

"At the beginning, as we boarded the bus, the driver was so nice," said Anargul Yusup, 40, one of the petitioners, who was traveling with her brother Rehim Yusup,  42, and a third person, Ghazi Hamud, 62.

"His first question to my brother was, 'Are you Russian?.' My brother answered, 'No, we are Uyghurs.' The driver then suspiciously looked at my headscarf and asked 'What you are doing here?'

"When I answered we are petitioners, the driver immediately stopped the bus, triggering the whole incident."

Irate passengers, many of them office workers, asked the driver to continue the journey but he informed them about a government notice ordering buses not to take Uyghur petitioners and insisted he call the police, according to the petitioners.

Ninety minutes later, the police arrived at the scene at Ganjiakou, a township-level division in the Chinese capital, and wanted to take the three away but they resisted.

They demanded that they be shown the notice from the authorities barring them from buses.

"The police wanted to take us to the police station for investigation but my brother jumped out of the bus and went in front of it and refused to allow it to move," Anargul Yusup said.

"We demanded that the driver come with us for the investigation process, resisting going to the police station."

The policemen then confirmed that the authorities had issued a secret notice to bus drivers warning them against taking Uyghur petitioners as passengers, she said.

"The police did not hide the [truth and] they explained that ‘the bus companies have been issued notices to not take petitioners, especially Uyghur petitioners, in Beijing’," Anargul Yusup said.

"The police explained that it was a secret notice and cannot be shown to the public."

After more than an hour of discussions, the police relented and set the petitioners free.

They advised the trio to sue the bus driver for the trouble, Anargul Yusup said.

"They also gave us a friendly advise: 'Next time, don't say you are petitioners, just say you are visitors or merchants.'

But she said, "We can hide our cases from the public but how can we hide our race?."

The policemen were not upset when the petitioners took down their personal details from their identification tags pinned on their uniform, the petitioners said.

The three petitioners were on their way to petition to the authorities over longstanding ethnic discrimination cases in Xinjiang, where the Muslim Uyghurs claim they are being persecuted for opposing Chinese rule in their homeland.

Uyghurs, who form a distinct, Turkic-speaking minority, say Beijing's policies favor Han Chinese migration into Xinjiang and the unfair allocation of resources to the Chinese.

Xinjiang has seen a series of violent attacks in recent years since July 2009, when ethnic tensions between Uyghurs and Han Chinese erupted in riots that left 200 people dead, according to the Chinese government’s tally.

Ghazi Hamud had gone to Beijing to raise the case of his son who was murdered by a Han Chinese in Xinjiang's northern Shihenzi city in 2001. The accused was only given a three-year jail term while Uyghurs facing a similar charge face executions, Hamud complained.

Anargul Yusup wanted to highlight her "unfair" job termination by her Han Chinese boss at the Aksu Public Transportation Company in Xinjiang.

"We have faced various forms of ethnic discrimination before—while we apply for jobs, register to stay in hotels or other accommodation places—but this is the first time we are asked to get out of a bus because of our race," Ghazi Hamud said.