SHANGHAI — Heavily armed soldiers and riot police dealt with a myriad of skirmishes and bloody scuffles Wednesday as they kept the lid on ethnic violence in Urumqi, but visibly failed to diffuse the tension after three days of ethnic riots that have left 156 dead and more than 1,000 wounded.

Chinese President Hu Jintao cut short his official visit to Italy and cancelled his appearance at the G8 summit to fly home to take control of the situation that has pitted ethnic Uyghurs against the majority Han Chinese population in the capital of the restive Xinjiang province.

The unprecedented situation of having unrest at home interfere with Hu's foreign agenda will be seen as an embarrassment to the "face" conscious Chinese leader, but the situation in Urumqi is volatile and no important decision can be made by the Communist party politburo without him at the table. He needs to be in China and ready to act if Urumqi erupts again.

His presence, however, only serves to underline for the world how seriously his government sees the unrest.

On the streets in the regional capital, rival protesters clashed verbally across barricades at several points and a few times managed to mix it up physically Wednesday, but for the most part security forces in riot gear and some carrying rifles with fixed bayonets, managed to keep the warring sides apart.

People were taken aback by the sheer number of military reinforcements that were put on the streets overnight and by the constant hum of the helicopters that were for the first time patrolling the skies overhead.

At a press conference Li Zhi, the Communist party chief in Urumqi, added to the deterrent factor, telling a press conference: "Those who brutally killed in the incident, we will sentence them to death."

Urumqi airport bore testimony to the violence that has wracked the desert city since Sunday. It was crowded with people looking to find just about any flight out to safety. The official Xinhua News Agency quoted one traveller saying: "We fear Xinjiang is not safe anymore."

Urumqi, a city of 2.3 million, has a majority Han population, but Turkic-speaking Muslims, known as Uyghurs, account for 45 per cent and crowd the bottom rungs of the social and economic ladder. It was their peaceful demonstration protesting police inaction over the death of two Uyghur workers in southern China that lit the tinderbox in Urumqi that sparked Sunday's riot. At least, that is the Uyghur side of the story.

The Chinese government maintains foreign agitators led by 62-year-old businesswoman Rebiya Kadeer, exiled leader of the World Uyghur Congress, "masterminded" the unrest in a bid to split China.

The two sides also disagree on what happened Sunday night, specifically how the march got so far out of control that 156 people died. Indeed, even the death toll is in dispute. Chinese officials say it comprises mostly Han Chinese killed by the Uyghur mob and police say they have rounded up 1,434 "suspects" so far. Uyghur groups challenge the death count, however, claiming it could be as high as 400 and saying the majority are Uyghurs, killed by security forces and the Han Chinese.

Around the world, governments have urged Beijing to exercise restraint with the protesters, but concern for the Uyghurs has been half-hearted when compared to the outpouring of support for the Tibetan protesters/rioters in Lhasa last spring when fewer than 20 were killed, according to official figures.

On Wednesday, the Turkish newspaper Hurriyet charged to the defence of the Turkic-speaking Uyghurs. It called the Chinese response to Sunday's protest a "massacre" and claimed military and police used "disproportionate force" against civilians.

The Turkish government appeared to be on the same wave length and called in the Chinese ambassador for talks. Foreign Minister Ahmet Davutoglu told reporters at a press conference in Istanbul, "The Uyghurs are a community of ethnic brothers whose fate concerns us."

He added: "There is an humanitarian situation there that requires the world's attention. It is out of the question for Turkey to remain indifferent."

The Chinese government is making no attempt to bury the events in Xinjiang, but Chinese outside of Urumqi are getting only a partial picture, at best, of what is happening. CCTV, the state television network, neglected, for instance, to show footage of Han Chinese on the rampage Tuesday. Many newspapers reported on the revenge march, but usually buried deep down in stories that focused on the damage caused by the Uyghurs.

Initially, Uyghur demonstrators used Facebook and Twitter to organize their protest, but both social networks are now blocked in China, as are large swathes of the Internet. In Urumqi, the whole "public" Internet is blocked, as well as much of the cellphone network. The government has made Internet available on one floor of a five-star hotel in downtown Urumqi for the international media.

Many in China regard "technical difficulties" caused by the government as a challenge, however, and an increasing number of "tweets" are turning up and being shared widely. One that was originally in Chinese but translated for the web reads: "Ministry of Public Security and Central Propaganda Department requirement: In order to reconcile conflicts between Han and Uyghurs, all publicity of this event should follow the tune of Xinhua News Agency and People's Daily. But it needs to expose the crimes of the East Turkestan movement as much as possible, let the masses understand the real face of the East Turkestan movement. Above information came from oral messages of insiders in the central government."

The unrest in Urumqi has sparked lots of Internet comment, both rational and irrational, but the government obviously doesn't want to encourage it.

On Wednesday, Tianya, a busy Chinese-language Internet forum used by thousands, abruptly posted a notice saying because of events in Urumqi the forum would clear off and block the IDs of comments that: "1. Incite ethnic hatred and advocate bloody violence; 2. Attach and revile the Party or the government; 3. Spread rumours or gossip."