In March, the woman had filed a first information report against two men.

Highlights 23-year-old woman from Uttar Pradesh's Unnao is critical

She had filed a rape case against two men from her village

Three men, including one of the accused, have been arrested

A 23-year-old woman, set on fire on Thursday morning by the men she had accused of rape, walked nearly a kilometer screaming for help before a witness saw her and called the police in Uttar Pradesh's Unnao. The woman was on her way to a local court for a hearing on her rape case when just outside her village, five men poured kerosene on her and set her on fire.

After dialing the emergency 112 helpline, the witness held his mobile phone on speaker so that the badly burnt woman could speak to the police.

She suffered 90 per cent burns and is critical. She was air-lifted to Delhi later in the evening, and then a green corridor was provided to her ambulance from the airport to the Safdarjung Hospital, helping her cover 13 kilometres in just 18 minutes.

The incident has horrified the nation just days after the rape and murder of a young veterinarian in Telangana, which has led to calls for tough and quick punishment of four accused men.

The woman's five attackers included the two men she had accused of raping her, said the police. One of them had been missing and the other was released on bail last week.

"We saw her coming towards us, screaming for help. She had been set on fire. We were scared. She had walked for nearly one km before she reached us," one of the eyewitnesses who called for help told reporters. She was rushed to a specialised hospital in Lucknow.

In the evening, she was shifted to Delhi's Safdarjung hospital. A green corridor had been created in Lucknow to move her from the hospital to the airport for the flight to Delhi.

In March, the woman had filed a first information report against two men, who are from her father's village in Unnao, accusing them of raping her and filming the act. The FIR was filed in the neighbouring Rae Bareli district reportedly after the intervention of a local court.

"In her FIR, the woman said that one of the two accused was in a relationship with her in 2018 but he physically exploited her, lured her with a marriage proposal. Later, he refused to get married and raped her with another friend," said SK Bhagat, senior police officer from Lucknow.

"One of the accused was sent to jail. He was released on bail on November 30. The two men set the 23-year-old afire to take revenge," he added. The police claim to catch the other accused, who had been on the run, they had seized his property and put out lookout notices against him.

Amid attacks by the opposition parties over the incident, the state government has told the police to ensure "maximum punishment" for the accused. UP Chief Minister Yogi Adityanath has also sought a report from the state police and has promised to fund the woman's treatment.

UP Director General of Police OP Singh told NDTV: "Our first priority is to save the woman. The criminal justice system has three-four compartments but we do not work like that. I do not want to blame anyone. The fact is that we did arrest one of the accused. I will get more facts on the case but I am sure that the local police would have opposed the bail application of the rape-accused."

The incident has prompted sharp attacks on the state's ruling BJP. In a tweet, Congress leader Priyanka Gandhi said the BJP "should stop spreading false propaganda". "Yesterday, the home minister of the country and the Uttar Pradesh chief minister clearly lied that law and order in Uttar Pradesh has improved. Seeing such incidents everyday angers the mind. BJP leaders should stop spreading false propaganda," Ms Gandhi wrote in Hindi.

The Nationalist Congress Party's Supriya Sule also commented on the incident in a series of tweets. "Extremely sad and shocked to hear that that Unnao Rape victim was burnt earlier this morning. If the culprits were not shielded and prosecuted on time this wouldn't have happened. Complete state of Lawlessness in the state of Uttar Pradesh...." she wrote.

@PMOIndia - The Central government speaks about - 'Beti Bachao - Beti Padhao', however, this seems to be a mere slogan if the daughters of our Nation are not protected.. (3/3) — Supriya Sule (@supriya_sule) December 5, 2019

Rajya Sabha MP and Samajwadi Party leader Ram Gopal Yadav said: "President's rule should be imposed in UP where Jungle Raj is prevalent. There is no law and order in the state."

Unnao BJP MP Sakshi Maharaj said the incident was "unfortunate". "The Unnao incident is really unfortunate. I have used all my power so that the investigation is done and the accused get punishment. The accused in such heinous crimes should get capital punishment," he was quoted as saying by news agency ANI.