A sex attacker raped a stranger less than three weeks after he had been freed early from jail.

Mark Arnott attacked the terrified 18-year-old at a car park near Dundee University on November 23, 2017.

He initially grabbed the medical student and told her: "Come with me. I have got a knife. I will stab you."

The 37-year-old forced the young woman to have sex before her cries for help were heard by people who had been at a nearby dance class.

At the High Court in Glasgow on Friday, a judge heard how Arnott had only been back on the street for 20 days when he struck.

He was on licence having earlier been jailed for robbery, and the sentence had not been due to expire until May 2020.

The court heard how the victim was walking near the car park in Dundee's West Henderson's Wynd as Arnott stood nearby smoking a cigarette.

He then ran up behind the teenager and grabbed her, which was later seen on CCTV, and dragged her into the car park.

The teenager said she feared being stabbed and tried to break free, and then noticed he was clutching a condom packet.

Prosecutor Lynsey MacDonald said: "She pleaded 'no, no, please don't do that to me'."

Arnott demanded she strip, forced her over the bonnet of a car and raped her.

The court heard Arnott also lied about his name and said that he was a 26-year-old navy engineer.

As her ordeal continued, the young woman noticed people leaving a nearby dance class, so yelled "I am being raped. He is raping me."

The attacker then ran off, and one woman started to chase after him.

After Arnott was identified, a large-scale hunt began and he was traced three days later.

He pled guilty to the rape charge and was remanded him custody as sentencing was deferred for reports.

The court heard the victim now does not go out alone at night and is awaiting to see a psychologist.

Lord Mulholland told Arnott: "Be in no doubt about it - this was a horrific ordeal for a young woman to endure at your hands."