A 16-year-old girl was left "extremely shaken" after she was raped at knifepoint in a field, say police.
The girl was grabbed in an alley in the Newton area of Hyde, Greater Manchester, as she walked to a friend's house at 2330 BST on Thursday.
The man forced her to walk from Cedar Street to a nearby field off Ashton Road close to the Senior Service cigarette factory where he raped her.
She was left in the field and called the police from her friend's house.
The man is described as white, in his mid 20's, slim, wearing blue jeans, a dark coloured jacket and a black balaclava.
"The girl has been left extremely shaken by this ordeal and we need to find the man responsible as soon as possible," said Det Sgt Gareth Davies from Stalybridge CID.
"I would urge anyone who may have seen a man fitting this description, acting suspiciously around the area, to get in touch with us."