A Chinese court today upheld the death sentences of three Uygur men involved in the gruesome knife attacks that killed 31 passengers at a railway station in Kunming city earlier this year.

The attacks occurred on March 1 when a group of Uygurs launched a stabbing spree at the crowded railway station in the southwestern city, killing 31 people while over 140 others were injured.

Iskandar Ehet, Turgun Tohtunyaz and Hasayn Muhammad were sentenced to death on September 12 for leading a terrorist organization and intentional homicide.

Investigators found that the three men had been training recruits for terrorist activities, including the attack at Kunming railway station, since December 2013, state-run Xinhua agency reported.

The native Uygur Muslims of Xinjiang province have been restive in the past few years over increasing settlements of Han Chinese from other provinces.

China blames the East Turkestan Islamic Movement (ETIM), an al-Qaeda backed organisation for various violent attacks in Xinjiang and other parts of China.

The Kunming attack too was reported to have been carried out by ETIM militants.

All three men along with some women associates were arrested for allegedly planning to illegally cross the Chinese border on February 27, just days ahead of the attack.

After failing to establish contact with Iskandar, five members of the group carried out their attack as originally planned on March 1.

Four were shot dead at the scene by the police while a woman, Patigul Tohti, weakened by a bullet wound, was captured.

Patigul was sentenced to life for participating in the attack as well as intentional homicide during the first trial.

The court ruled that although her criminal acts were extreme, as she was pregnant at the time of the arrest, she would be handed a life sentence.

The Yunnan Higher People's Court rejected Muhammad's appeal today and upheld the penalty meted out by the Kunming Municipal Intermediate People's Court last month.

The higher court affirmed the facts and evidence of the first trial and upheld the judgment and sentences.

The higher court ruled that all three suspects were guilty of organising, leading and plotting violent, terrorist attacks and they should take responsibility for all the crimes committed and organised by their terrorist cell.