Chinese officials have blamed separatists from the north-western Xinjiang region for a mass knife attack at a railway station that left 29 people dead and at least 130 wounded.
A group of attackers, dressed in black, burst into the station in the south-west city of Kunming and began stabbing people at random.
Images from the scene posted online showed bodies lying in pools of blood.
State news agency Xinhua said police shot at least four suspects dead.
A female suspect was arrested and is being treated in hospital for unspecified injuries while a search continues for others who fled the scene, the BBC's Celia Hatton in Beijing reports.
Authorities described the incident as an "organised, premeditated, violent terrorist attack".
The Kunming city government later said that evidence from the scene pointed to separatists from Xinjiang as being behind the attack.
It gave no details and the claim could not be verified.
Some of Xinjiang's minority Uighur Muslims want autonomy from Chinese rule and an end to state suppression of their religion.