Detectives are urgently trying to find Carmelle Hepi who was reported missing by her "desperately worried" family on Sunday.

The teenager, from Barnsley in South Yorkshire, travelled to Sheffield on Saturday before catching a train to Kings Cross St Pancras station in London, where she arrived shortly after 6pm.

Police believe she went to a birthday party involving a small group of teenagers in Peckham, southeast London, on Sunday night.

She is thought to have left the party in a car with another group of people at about 11pm on Sunday, and also visited properties in Croydon, Lewisham and Purfleet in Essex.

Officers believe Carmelle "may now be in the company of an older male" but their location is unknown.

The Metropolitan Police said three men in their 20s have been arrested on suspicion of kidnap and remain in custody.

The force said officers had spoken to people who were at the party and "there is no information at this time to suggest that Carmelle has come to serious harm".

However, it added that detectives from specialist crime are leading the investigation due to the missing girl's "age, vulnerabilities, and concerns around who she may be associating with".

Police have released an image of Carmelle, which is believed to have been taken in a car in the Peckham area on Sunday.

CCTV footage also shows the teenager, wearing a pink and white jacket, entering a Primark store in Croydon.

Family 'cannot rest'

In a direct message to Carmelle, Detective Chief Inspector Chris Wood said: "Carmelle, I want you to know that you are not in any trouble whatsoever. Our one and only focus is making sure that you are safe and well.

"Please call 999 and speak to us, or go to a police station, and we will get you back home safely.

"Your family are desperately worried about you and while we're supporting them as best we can, they need to know that you're okay and to come home.

"They cannot rest until you're back with them."

DCI Wood said his team was "working round the clock" to find Carmelle along with officers from South Yorkshire Police.

A number of properties have been searched in a bid to trace the teenager, he added.

In a message to the public, the DCI said: "If you have seen Carmelle, or you know her and have information about where she is or has been, it is imperative that you contact us.

"It doesn't matter if you're a friend who has heard or seen something in passing - you won't be in trouble.

"What matters is that you contact us as you could have significant information to help us find a missing teenage girl."