At least 31 people were killed at a busy street market in north-west China yesterday when two vehicles ploughed through shoppers and set off explosives.

More than 90 people were injured in the city of Urumqi, Xinjiang region — the bloodiest attack in a campaign of violence that Chinese authorities have blamed on radical separatist Muslim Uighurs.

The Xinjiang regional government said that the early-morning strike was “a serious violent terrorist incident of a particularly vile nature.”

The vehicles crashed through barriers and drove into crowds of shoppers.

They then crashed head on and one of them exploded. There were up to a dozen blasts in all.

There was no claim of responsibility for the attack but recent violence has been blamed on Turkic Uighur Muslim groups seeking independence.

Urumqi was the scene of a bombing at a train station last month that killed three people, including two attackers, and injured 79.

Security in the city has been significantly tightened since that attack, which took place as President Xi Jinping was visiting the region.

Mr Xi pledged yesterday to “severely punish terrorists and spare no efforts in maintaining stability.”

Public Security Minister Guo Shengkun was also dispatched to Urumqi at the head of a team to investigate the incident.

The bombing came just two days after Xinjiang courts jailed 39 people who were convicted of crimes including organising and leading terrorist groups, inciting ethnic hatred, ethnic discrimination and illegally manufacturing guns.