Fresh ethnic clashes erupted in the capital of China's northwest region as thousands of Han Chinese and local Uighurs armed with makeshift weapons were locked in a tense standoff.
Thousands of Chinese troops flooded the city in the wake of massive riots that officially left 156 dead.
But exiled Uighur leader Rebiya Kadeer put the toll as high as 400.
The scale of the ethnic clashes forced Chinese President Hu Jintao to cut-short his official visit to Italy for the G-8 summit and rush back home, Chinese Foreign Ministry said.
Hu's sudden return came as fresh ethnic clashes were reported in this capital as thousands of Han Chinese marched through the city looking for local Uighurs.
To confront China's worst ever secular fight, thousands of troops armed with semi-automatic weapons, armoured cars and heavy batons cut the city in half to separate the warring groups.