A court in China's restive Muslim-majority region of Xinjiang sentenced three men to death on Tuesday after they were found guilty of trying to hijack an aircraft and detonate explosives, state media said.

The men, along with a fourth who received a life prison term, were among a group of six that tried to seize the aircraft after it had taken off from Hotan in the northwestern region and were thwarted by passengers and crew, the official Xinhua news agency said, citing a court statement.

The other two gang members died in the struggle, which also resulted in injuries to 24 crew members and passengers, the statement said.

They were confronted after they tried to "detonate explosive devices", the statement from the Intermediate People's Court in Hotan Prefecture said, adding that "converted metal crutches and explosives" were used in the hijacking.

The men attempted to commandeer the Tianjin Airlines flight 1,400km away from its destination, the regional capital city of Urumqi.

They were influenced by religious extremists and "loudly shouted religious extremist cries" on board the aircraft, the Xinhua report said, citing court testimonies.

"They decided to blow up the aircraft and die along with all the other passengers," it added.

Ringleaders Musa Yvsup and Arxidikali Yimin, along with Eyumer Yimin, who played a major part in the attempted hijack, were sentenced to death.

Alem Musa received a life sentence as he played a minor role in the incident and showed "a good attitude" after being arrested, according to the statement.

"All the defendants confessed the above crimes at the court," the report added.

However, Dilxat Raxit, a spokesman for the exiled World Uyghur Congress, disputed the official version of events, claiming that a fight over seating broke out on board the aircraft between a group of Uighurs and Han Chinese, the country's majority ethnic group.

"The men who were sentenced were not allowed their own lawyers, only those that were given to them by the government," he said.

"The Xinjiang people believe this has been arranged for the Chinese authorities' political purposes. They could use this to step up suppression of the Uighur people. We believe the whole thing has no transparency."

Xinjiang is home to around nine million Uighurs, many of whom complain of religious and cultural repression by Chinese authorities -- a claim the government denies.

The vast resource-rich region, which borders Pakistan and Afghanistan, has been under heavy security since July 2009, when bloody ethnic riots in Urumqi killed 197 people and injured around 1,700.

Rights groups say the violence in the region stems from long-held grievances among Uighurs, who complain that an influx of Han is eroding their culture.

Beijing says it has provided much-needed development in the region, and blames much of the violence there on what it calls the three "evil forces" of religious extremism, separatism and terrorism.

The attempted hijack resulted in an 'economic loss' of 28.58 million yuan (4.58 million U.S. dollars), the court statement said.

Such incidents on Chinese planes are rare, although in October a man was arrested for allegedly making a hoax threat that forced a plane into an emergency landing, state media said.

The China Southern Airlines flight had originally taken off from Istanbul in Turkey and landed in Urumqi. It was en route for Beijing when the alert happened.

Last year a plane bound for Urumqi was forced into an emergency landing after a passenger claimed there was a bomb on board.

Police detained the 27-year-old woman passenger after she threatened to detonate explosives during the China United Airlines flight from Beijing to Urumqi.