Uighurs in Kazakhstan rally against China crackdown

* Uighurs in Kazakhstan express anger at treatment in China

* Official demands investigation, seeks international help

(Adds investigation)

ALMATY, July 19 (Reuters) - Thousands of ethnic Uighurs rallied in the Kazakhstan city of Almaty on Sunday to protest against a crackdown against Uighurs in the neighbouring Chinese region of Xinjiang.

Around 5,000 Uighurs, including women wearing white scarves as a sign of mourning, gathered in a Soviet-era congress hall in Kazakhstan's biggest city to express their anger at China's crackdown in its northwestern Muslim region.

"Freedom to Uighurstan!" shouted the crowd after a minute's silence, shaking fists and waving blue flags with white crescents symbolising the Uighur independence movement.

In Xinjiang's worst ethnic unrest in decades, Uighurs staged protests in the regional capital Urumqi on July 5 after a clash at a factory in south China in June left two Uighurs dead.

The violence left 197 people dead and more than 1,600 wounded, mostly Han Chinese who launched revenge attacks in Urumqi days later, according to China's government. About 1,000 people, mostly Uighurs, have been detained in an ensuing government crackdown.

Kakhraman Khodzhaberdiyev, an official from the U.S.-based World Uyghur (Uighur) Congress, told Reuters they wanted an investigation led by the likes of the United Nations, Amnesty International and Human Rights Watch (HRW).

"We want to know the truth. China is always lying ... but I am pessimistic," he said, adding that Western nations were unlikely to push for such an investigation for fear of spoiling relations with China, an important trading partner.

"China may not let anyone in (to conduct such an investigation) but we must do everything possible. It may be just a cry of despair."

Uighurs are a largely Muslim Turkic people who share linguistic and cultural bonds with Central Asia.

Kazakhstan is home to their largest community outside of China and many more are scattered around the rest of the Central Asia region where Uighurs want to set up their own state.

The Xinjiang violence has stoked tension among Kazakhstan's Uighurs and lent a broader sense of instability to the vast region bordering Afghanistan.

During the rally in Almaty, about 10 hours drive from Urumqi, a mullah in white robes chanted a prayer in honour of those who died during the riots while others gave speeches and read out poetry.

"We can't stay silent. It was a bloody crackdown on our people in Urumqi," said Abdureshit Turdiyev, vice secretary-general of the World Uyghur Congress.

"Repression against our people is continuing in China."

Kazakhstan, a nation of 15 million, is run by an authoritarian leadership and rarely allows any public form of discontent. There have been no big public manifestations by Uighurs in any other parts of Central Asia.

Many Uighurs, who deny they could use force to gain independence, have accused the West of ignoring their plight and appealed to global powers to condemn China's actions. (Editing by Alison Williams)