Trucks carrying hundreds of Chinese troops roll through the centre of Urumqi.

Security has been heightened and police are on alert, just days after one of the country's deadliest attacks in the troubled Xinjiang province.

Chinese state television announced on Saturday that the authorities have launched a one-year crackdown to hunt down and punish militants in Xinjiang.

It comes after thirty nine people died and 90 were wounded on Thursday when two vehicles drove into crowds at a market in Urumqi and threw explosives.

In a show of force, China's Minister of Public Security spoke to hundreds of troops and police nearby, inspecting officers on the streets.

He also attended a ceremony commemorating the victims of Thursday's suicide attack.

Police say they have identified the five suspects. They all appear to be Uighur.

Xinjiang, which is home to the Muslim Uighur minority has seen a spate of attacks in recent years.

Beijing has blamed these