A Uighur activist in Japan said 1,000 Chinese police confronted some 3,000 Uighur demonstrators in Urumqi, the capital of western Xinjiang region, on Sunday in a clash that left two people dead.
The head of the Japan Uighur Association, Ilham Mahmut, told AFP that he had also heard that at least 300 people had been arrested, citing Internet communications from China.
"At 5pm local time about 3,000 Uighur people gathered in Urumqi and demonstrated and about 1,000 Chinese police confronted them, and I heard that two Uighur people are already dead," Mahmut said.
"The Chinese police tried to disband the demonstration and they used electric cattle prods and they fired guns into the air as warning shots.
"As we speak about 300 Uighur people have been already arrested and I've heard two people died because Chinese police used electric cattle prods."
He added that demonstrators were regrouping to continue their protest.
"About 400 people are trying to resume the demonstration," he said, speaking about 11 pm Japan time.
He said the tensions were sparked by a recent violent dispute at a toy factory between Chinese and Uighurs sparked by a rumour that Uighurs had abused a Chinese woman.