A Chinese teenager executed after being convicted of murder and rape 18 years ago was declared innocent by a court Monday, in a rare overturning of a wrongful conviction.

The 18-year-old, named Hugjiltu and also known as Qoysiletu, was found guilty and put to death in Inner Mongolia in 1996, but doubt was cast on the verdict when another man confessed to the crime in 2005.

"The Inner Mongolia Higher People's Court finds Hugjiltu's original guilty verdict... is not consistent with the facts and there is insufficient evidence," the court in Hohhot said in a statement.

"Hugjiltu is found not guilty."

To howls of anguish, the dead man's mother, father and brother burned a copy of the court decision on his grave, footage on news portal Netease showed.

His brother Zhaoligetu told Sina.com: "My mother wished him 'rest in peace' and hoped he could reincarnate."

Campaign groups and experts welcomed the court decision and said it was a signal to the rest of the justice system that it must perform better.

China's courts, controlled by the ruling Communist Party, have a near-100 percent conviction rate in criminal cases and confessions extracted under dubious conditions are commonplace.

Leaders of the ruling communist party have promised to strengthen the rule of law "with Chinese characteristics", but experts caution the concept refers to greater central control over the courts, rather than judicial independence.

The court's deputy president gave Hugjiltu's parents compensation of 30,000 yuan ($4,850), the official Xinhua News Agency reported. The money was a personal donation by the head of the court, it added, rather than an official payment by the institution.

"This is an amazing thing the court did, to admit that they were wrong," said Wang Gongyi, deputy director of the research institute of the Ministry of Justice.

"It also sends a clear message to the police and prosecutors around the country: if there's not enough evidence, don't impose wrongful convictions," he told AFP.

"In the future this case will be singled out as what not to do and will influence the entire legal system."

- Grave miscarriage -

In Hugjiltu's case, authorities interrogated the teenager for 48 hours, after which he confessed to having raped and choked the woman in the toilet of a textile factory, the state-run China Daily newspaper reported in November. He was executed 61 days after the woman's death.

Hugjiltu's family tried for nearly a decade to prove his innocence, according to reports, and the Higher People's Court officially began a retrial in November.

It said Hugjiltu's confession did not match the autopsy report and was inconsistent with "other evidence", and that DNA evidence presented at the trial did not definitively connect him to the crime.

Police in Hohhot, where the crime took place, said they opened an investigation into the officers responsible for the original case, according to the Legal Evening News.

Many on social media decried what they saw as insufficient compensation for such a grave miscarriage of justice, with one asking: "Is 30,000 yuan really enough to buy the life of a family member?"

China executes more people than the rest of the world combined, according to rights groups. The country put an estimated 2,400 people to death last year.

"The central government wants to use this case to send a clear signal to police and courts that they need to do a better job," said William Nee, China researcher at Amnesty International.

"But without transparency in death penalty cases, it will be hard to determine if progress is being made."

China has occasionally exonerated wrongfully executed convicts after others came forward to confess their crimes, or in some cases because the supposed murder victim was later found alive.

In one case, police claimed a body was that of a woman who had recently disappeared and charged Teng Xingshan with her murder. Teng was executed by firing squad in 1989, but in 1993 the supposedly murdered woman returned to the village saying she had been kidnapped.

Teng was exonerated of all crimes in 2005.

Several other high-profile wrongful convictions have sparked public outrage in recent years.

Last year, a man who served 17 years in prison for killing his wife was declared innocent by an appeals court in the eastern province of Anhui.

A few months earlier two men who had been sentenced to death and life in prison in 2004 for the alleged rape of a 17-year-old girl were also acquitted.