A Portsmouth university student was grabbed by intruders as she arrived home after a night out.
Police said the victim, 20, found two men in her room at Harry Laws Halls in the city centre on Thursday at 2330 GMT.
One of the intruders grabbed the woman and pushed her on the bed before showing her a knife.
The men went through the victim's belongings before leaving with cash and a mobile phone.
The first man is described as black, in his mid to late 20s, 5ft 7ins tall, of medium build, unshaven and wearing a shiny black hooded jacket which was white underneath. He also had acne scars on his cheeks and jaw line.
The second man is described as black and of a similar height and build. He was wearing a black hooded top.
Det Sgt Tony Lewis, of Hampshire Constabulary, said: "The victim had been for a night out with friends and had returned to her room to change her shoes.
"Thankfully she's uninjured but is clearly upset at what's happened and spent the night with friends.
"As part of our investigation we'll be producing e-fits of the suspects and studying CCTV.
"In the meantime I want to hear from anyone who saw either man hanging around Harry Law Halls last night either inside or outside, or anyone who knows who they are."
Det Sgt Tony Lewis urged all students to lock their bedroom and front doors when going out and not to let anyone in who they did not recognise.