Chinese authorities said Monday that they have arrested three more suspects in an attack Saturday in which knife-wielding assailants killed 29 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, and late Monday night, police identified as the leader of the attack 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 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.”

The Ministry of Public Security’s criminal investigation division posted on its social media account that it had linked five of the suspects to the attack using “interviews, forensic examination, fingerprint comparison and DNA inspection.”

At least 29 people were killed and more than 140 wounded during the attack Saturday night. Within hours of the assault, the government declared it a “premeditated violent terrorist attack.” And many Chinese online have likened it to their country’s version of the Sept. 11, 2001, attacks in the United States.

A coordinated attack of this size and nature is rare in China. China’s leaders quickly responded with statements from top officials vowing “all-out efforts” to punish the perpetrators.

Human rights groups and Uighurs expressed concern that the incident might cause a backlash against Uighurs in the country and result in even heavier security. State media editorials Monday called for increased measures against terrorism in Xinjiang.

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 longstanding complaints of discrimination and oppression by Uighurs in their coverage of the attacks.

Many called such Western coverage of the stabbings hypocritical attempts to justify terrorism. “US double standard on terrorism encourages slaughters,” read an editorial by Xinhua News Agency.

When asked about some foreign governments who denounced the attacks without explicitly calling it “terrorism” — as the U.S. Embassy in Beijing did on its social media account — China’s foreign ministry spokesman Qin said, “Bloody facts are placed in front of the world. … We hope, when dealing with such violent terrorists, the international community should speak with one voice and take the same actions.”

The attack comes at a particularly sensitive time, as top officials from China’s Communist Party are gathering for their most important public meeting Wednesday, an annual convening of its largely rubber-stamp legislature in Beijing. Many comments about the attack have been censored on Chinese social media.

For years, ethnic rioting and clashes have taken place in Xinjiang. Separatists in Xinjiang who seek full independence from China call the Xinjiang region “East Turkestan” and want the right to govern themselves. But Saturday’s attack, along with another attack in October in which a jeep was crashed into Tiananmen Square, suggest that the conflict has morphed into a possible new trend of targeted terrorist strikes in major cities far from Xinjiang.

While condemning such violence, many Uighur groups have said general antipathy toward the Chinese government in Xinjiang is a reaction to oppressive official policies, religious restrictions and widespread discrimination.

The Chinese government has long denied any oppression or discrimination against Uighurs or other ethnic groups.

Hallie Gu contributed to this report.