China has sentenced three men to death and a woman to life in prison for a knife-wielding attack at a train station that killed 31 people and left more than a hundred others injured.

The three men, believed to be from the Uighur Muslim minority, were convicted on Friday of "leading a terrorist group" which planned and carried out the stabbing spree, the Intermediate People's Court in Kunming said in a statement.

The court said the suspects, influenced by religious fundamentalism, plotted the March 1 attack when five knife-wielding assailants hacked 31 people to death and injured another 141 people.

Local authorities arrested Iskandar Ehet, Turgun Tohtunyaz and Hasayn Muhammad, two days before the attack as they were attempting to illegally leave China.

Having lost the contact with the three men, five other members of the group mounted the attack as planned, the court said.

Police shot dead four members at the scene and captured the fifth, Patigul Tohti, the court heard.

Tohti was jailed for life for taking part in the attack as well as intentional homicide, but had her death sentence commuted to life in prison because she was pregnant.

Exiled rights groups blame China's repressive ethnic policies and practices as well as economic disenfranchisement of Uighurs, who sometimes attempt to escape China and seek asylum in Southeast Asia.

Dilxat Raxit, spokesman for the World Uyghur Congress, told the Reuters news agency, "China should take the main responsibility for promoting policies of hostile repression that triggered this incident."

Beijing has vowed to strike hard at separatist groups, which they blame for a series of violent attacks in Xinjiang, the traditional home of the Muslim Uighur ethnic minority.

China's courts have a near-100 percent conviction rate and the death penalty is regularly handed down in terrorism cases.

Source: Agencies