The violence in Kunming came at a sensitive time as political leaders in Beijing prepared for Wednesday's opening of the annual meeting of the nominal legislature where the government of President Xi Jinping will deliver its first one-year work report.
Xi called for "all-out efforts" to bring the culprits to justice. In a statement, the Security Management Bureau under the Ministry of Public Security said that police will "crack down the crimes in accordance with the law without any tolerance."
A Xinhua reporter on the scene in Kunming said several suspects had been "controlled" while police continued their investigation of people at the train station. The reporter said firefighters and emergency medical personnel were at the station and rushing injured people to hospitals for treatment.
Authorities said five suspects were shot dead but that their identities had not yet been confirmed, and police were hunting for the remaining attackers, Xinhua reported. The news agency said 29 people described as civilians were confirmed dead and 130 injured.
More than 60 victims of Saturday's attack were taken to Kunming No. 1 People's Hospital, where at least a dozen bodies also could be seen, according to Xinhua reporters at the hospital.
At a guard pavilion in front of the train station, three victims were crying. One of them, Yang Ziqing, told Xinhua that they were waiting for a train to Shanghai when a knife-wielding man suddenly came at them.
"My two town-fellows' husbands have been rushed to hospital, but I can't find my husband, and his phone went unanswered," Yang sobbed.
Footage on China's state broadcaster CCTV showed a heavy police presence near the station and plainclothes agents wrapping a long knife in a plastic bag as investigators collected evidence following the attacks.
Pictures on Sina Weibo, the Chinese equivalent of Twitter, showed bodies covered in blood at the station.
The Kunming railway station, located in the southeastern area of the city, is one of the largest in southwest China.