China’s Kunming railway station saw security stepped up after a mass knife attack resulted in the deaths of at least 33 people and left over 130 injured.

Four suspects were shot dead, while a further person – thought to be female – is being detained and others are believed to have fled the scene.

According to one eyewitness, a group – mostly wearing black – rushed into the station and started to attack people with knives.

Chinese authorities have blamed militants from the restive, far-western region of Xinjiang for Saturday’s assault.

It is the first time people from this area have been blamed for an attack so far from their home region.

China heightened security in Xinjiang from October 2013 when a vehicle drove into tourists on the edge of Tiananmen Square, killing two bystanders, as well as the car’s three occupants.

The country labelled this a “suicide attack” by militants from Xinjiang, which is home to the Muslim Uighur people, many of whom are unhappy about restrictions placed on their culture and religion.

If the assault at Kunming Railway station is found to have been the work of militants from the same region, it will signal a considerable escalation in the simmering unrest which had previously only focussed on Xinjiang.

Officials have been ordered to track down those behind the attack. China’s president, Xi Jinping, was quoted by news agency Xinhua as saying authorities must:
“Severely punish the violent terrorists in accordance with the law, and resolutely crack down on those who have been swollen with arrogance.”

Just days before the opening of China’s annual parliamentary session, the incident in the southwestern city comes at a particularly sensitive time for the country. Security is normally tightened during this period each year.