Several days before Uighur demonstrators gathered in the streets of the northwest city of Urumqi last Sunday in a protest that began China’s bloodiest bout of civil unrest for 20 years, secret signs started appearing in taxi windows.

Local security chiefs missed the signals. The clues were important because they were alerting Uighurs in the capital of Xinjiang province to demonstrate against the Han Chinese.

The signals told the Uighurs to avenge the racially motivated killings of two Uighur migrant workers that had occurred last month in a toy factory in southern Guangdong province, triggered by rumours that they had raped several women.

As a result the authorities were caught off guard when the protests erupted, amid erroneous stories that the killers of the Uighurs had been allowed to go free.

The taxi signals suggest that the rioting by the Uighur minority was not entirely spontaneous. Having suppressed the violence by flooding the city with tens of thousands of troops and police, China’s authorities are hunting for a fringe of extremists who they accuse of organising the rioting. They have promised the ringleaders will be executed.

The riots are some of the deadliest on record in China since the 1966-76 cultural revolution; their seriousness was shown by President Hu Jintao’s cancellation of his trip to the G8 summit in Italy.

Taken unawares, the authorities had difficulty quelling the rioting as mobs of Uighurs and Han Chinese attacked each other with meat cleavers, clubs and shovels, turning the streets of the city into a bloody battleground for several nights.

Yang Jiandao, 44, a Han migrant worker from Henan province, moved to Urumqi several years ago as a decorator. On Sunday night he was on his way home when he was surrounded by a mob of Uighurs shouting and smashing cars.

He awoke in hospital, his face battered and bleeding, to learn that many of his workmates had died. “I do not understand. If the Uighurs feel angry with government policy they should demonstrate in front of government buildings or attack policemen, not kill and beat ordinary Han Chinese,” he said. “I came here only because I could not make ends meet in my home town.”

The authorities said that 184 died, 1,080 were injured and more than 1,000 suspects arrested. These grim statistics have undermined the notion propagated by the Communist party that the majority Han and ethnic minorities in China live in “harmonious coexistence”.

Unlike the brutal crackdowns in Tibet before the Beijing Olympics, the authorities allowed foreign journalists to report on the violence. They wanted the world to have the impression of openness. But for the Chinese it was a different story, as the authorities shut internet and phone services, in effect isolating the people of Urumqi.

China’s policies in the Xinjiang Uighur autonomous region have always been governed by fears that the province’s Uighurs – who are of Turkic origin and Muslim – want to secede from China. The vast province is rich in oil and gas and shares its border with Kazakhstan, Kirgyzstan, Pakistan and Russia. Maintaining stability and suppressing separatist movements is hugely important for Beijing.

One man has dominated policy in the province over the past 15 years. He is Wang Lequan, the local party chief, a member of the politburo, China’s ruling inner sanctum, with close ties to Hu. In the middle of the riots he moved swiftly to reassert authority, bringing in troops and delivering a tough address promising harsh punishment for troublemakers.

Wang has been the architect of policies that have restricted Uighur culture and religion. He replaced the Uighur language with Mandarin in primary schools and barred the wearing of beards and headscarves, fasting during Ramadan and praying by government workers.

But there is another side, too, leading to resentment among Han Chinese. They complain that he has allowed the Uighurs to have two or three children compared with just one for them. The Han also accuse him of showing greater tolerance to Uighurs when they commit crimes.

The violence raises serious questions for Beijing. For now there is a tense stability in Urumqi. But to maintain Wang’s authority, China will have to resort, as it did at Tiananmen Square, to violent repression. That may only fuel unrest.

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