At least six people have been injured in a knife attack at a station in Guangzhou, Chinese officials say. It is unclear how many people were involved in the attack, but one person was shot and then detained by police. There is no information yet on the motivation for this attack, but it comes a week after an attack at a station in Urumqi, in the western region in Xinjiang. It also follows an attack at Kunming station in March that killed 29 people. Chinese authorities have blamed both these attacks on separatists from the Uighur minority group, which lives in Xinjiang.