New Delhi (Reuters): India's top court on Friday upheld death sentences against four men who fatally gang raped a woman on board a bus in 2012.

The five men and a juvenile lured the 23-year-old trainee physiotherapist and her male friend on to a bus in New Delhi on Dec. 16, 2012, before repeatedly raping the woman and beating both with a metal bar and dumping them on a road.

The woman died of internal injuries nearly two weeks later in a Singapore hospital.

Applause broke out in court among relatives of the victim - whose identity is protected by law - as judges explained the crime met the "rarest of the rare" standard required to justify capital punishment in India.

"It's a barbaric crime and it has shaken the society's conscience," Justice R. Banumathi said, as a three-judge Supreme Court panel threw out an appeal on behalf of the defendants.

"I am very satisfied. Today I am happy," the victim's mother said outside the courthouse.

Her father said: "It's not just a victory for my family, it's a victory for each and every woman in our country."

Four of the attackers were sentenced to death 2013 while the fifth hanged himself in prison during the original seven-month trial. That verdict was upheld by the Delhi High Court in 2014.

The four - gym instructor Vinay Sharma, bus cleaner Akshay Kumar Thakur, fruit-seller Pawan Gupta and unemployed Mukesh Singh - then appealed to the Supreme Court. The defendants were not in court on Friday.