Thousands of police and troops have been deployed to quell the ethnic violence that is ravaging the Chinese city of Urumqi.More than 150 people have been killed and many more injured in the clashes between the Muslim Uighur population and Han Chinese. Police have made more than 1,400 arrests. The violence, which broke out on Sunday, followed years of tension in the Xinjiang region. Han Chinese migrants have poured into the area and Uighurs say they suffer severe discrimination. Many of them support calls for an independent Uighur state. On Tuesday, Han protesters took to the streets with weapons seeking revenge for Sunday’s attacks on their community and the situation remains volatile. The communist party chief in Urumqi, Li Zhi, said the government would execute those found guilty of killings during the riots. Security forces are trying to separate the two communities. There is anger on both sides about the number of arrests. President Hu Jintao has flown back from the G8 summit to deal with the situation. The Chinese authorities blame Uighur exiles for stoking the unrest.