BEIJING — Chinese authorities said Monday that they have arrested the last three suspects in the weekend attack in which knife-wielding assailants killed 29 people and wounded at least 140 at a train station, according to state media.

Authorities have blamed the attack on separatists from China’s restive Xinjiang region. Monday night, police said the leader of the attack was a man whose name appears to be from the Uighur ethnic minority that has long chafed under Chinese rule.

The gruesome attack Saturday, which left bodies strewn throughout the train station in the southern city of Kunming, threatens to worsen already strained relations between the country’s Uighurs and its ethnic Han Chinese majority.

China’s government-controlled Xinhua News Agency said Monday that the attack was carried out by a terrorist gang of six men and two women.

Four were shot and killed Saturday by authorities, and a female was arrested. Xinhua said the remaining three were arrested Monday afternoon. Earlier reports said more than 10 attackers were involved. Authorities did not explain the discrepancy.

Xinhua said the leader’s name is Abdurehim Kurban, but they did not say whether he was among those arrested or killed. At a news briefing Monday, Foreign Affairs Ministry spokesman Qin Gang said, “The flag of the East Turkistan Islamic Movement terrorist group was indeed found at the scene, among other evidence.”

In a sign of how emotionally charged the attacks have become, many Chinese state-run media and online users heaped scorn and launched online campaigns against Western news organizations Monday, including CNN, BBC and The Washington Post, for including long-standing complaints of discrimination and oppression by Uighurs in their coverage of the attacks.