A 24-year-old girl suffered serious burn injuries when two motorcycle-borne unidentified youth threw acid at her in the posh Hazratganj locality in Lucknow, the police said on Wednesday.

The incident occurred late on Tuesday night when the girl, a student of the National Institute of Fashion Technology, New Delhi, was returning home, the police said.

The victim's boyfriend Ankur, against whom her parents have filed a first information report in this regard, has been arrested, the police added.

The girl, who suffered 50% burns in the attack, is stated to be out of danger, the police said, adding the motive behind the crime was being investigated.