Four suspects, who allegedly planned, organized or took part in the Kunming knife attack in Yunnan province, causing 29 deaths and injuring 143 people on March 1, have been charged with being involved in a terrorist attack, the Supreme People's Procuratorate said on Monday.

The SPP said on its website that the four suspects, who are all from the Xinjiang Uygur autonomous region, are being prosecuted in Kunming City Intermediate People's Court.

According to the Kunming People's Procuratorate, which filed the charges, three of the suspects are accused of organizing or leading terrorist organizations or intentional homicide, and the fourth is charged with taking part in the terrorist organization and intentional homicide.

"The criminal facts are clear and the evidence is solid, and they will be criminally held accountable according to the law," said a statement released by the procuratorate.

On March 1, a group of knife-wielding assailants attacked civilians at a railway station in Kunming, provincial capital of Yunnan province.

Police shot four of the attackers to death at the station, and the other four were arrested and detained by police on March 3, authorities said.