Indian police have launched a manhunt for two rape accused after a gangrape victim alleged they threw acid on her face for refusing to withdraw the case.

The woman was reportedly raped by three men in May in India's northern state of Uttar Pradesh. One of the accused continues to be in police custody while the other two were recently released on bail.

The woman has suffered chemical burns on her face following the acid attack on Monday (11 September). She is currently undergoing treatment in a local hospital, the BBC reported.

The victim told police she was taken to a secluded spot by the two accused while she was returning home from a local court, where she had gone to prepare to contest their bail, Superintendent of Police Daya Nand Misra told the broadcaster.

The men demanded she withdraw the rape case and when she refused, they poured acid on her face, she reportedly said.

In the past, rape accused have attacked the victim after being granted bail. Women have been raped again, attacked with acid or even killed for filing cases against their molesters.

Laws have been tightened in India for crimes against women, including rape and domestic violence, after the 2012 Nirbhaya case where a medical student was brutally raped and killed by a group of men on a bus while she was returning home late evening with a male friend.

Recently, a tribal woman in the eastern state of Jharkhand was gangraped by at least six men for dating a man out of the tribe. She was returning home from university with her boyfriend when a group of men stopped them on the road, forced them to strip and have sex in front of them before taking turns to rape the girl. The alleged rapists were accompanied by another 10-12 friends.