TEENS and young people are being blackmailed by cyber-criminals who threaten to post pictures of them online.

Police are warning computer users of a new threat from foreign organised crime gangs who target social networking and online dating websites.

Victims are lured into private online conversations by con artists who set up fake profiles on dating sites, social media and instant messaging apps.

They are then tricked into giving out personal information and even posing for intimate photographs, allowing the fraudster to save the images.

A threat is then made to publish the pictures and private details unless money is paid.

Police insiders say they are investigating an increasing amount of incidents, but they believe the majority of online blackmail crimes are going unreported.

Last year, a number of operations led by Interpol's Digital Crime Centre led to the arrest of more than 60 people suspected of being involved in online extortion scams.

Raids and arrests were carried out across the world.

The recent spike in offences has prompted police in Lanarkshire to issue a warning for people to be vigilant.

A statement read: "Police are currently experiencing a rise in the number of complaints regarding online extortion.

"People are being contacted via social media by offenders, who have created fake profiles, and claim to be interested in the victims.

"As the conversations continue between both parties, a request is normally made for the victim to send private information, including images of themselves via private message.

"This information is then used to extort money from the victim.

"The offenders then request money claiming they will post images on social media to the victim’s friends, family and worldwide.

"The impact on these victims is horrific and many have transferred large sums of money via Western Union to these offenders."

Computer security experts say blackmail and extortion are a common way for online fraudsters to make money out of their victims.

In July 2013, Daniel Perry, 17, from Dunfermline, took his own life after he was targeted in an online blackmail scam.

According to Interpol, there are "hundreds of thousands of victims" around the world who become involved in online chats with someone they believe is interesting in being in a relationship with them.

The crime has become known as 'sextortion'.

Often, men are targeted by fraudsters posing as attractive young women.

The Police Scotland warning added: "Please don't be caught out.

"The offenders will not stop requesting money, placing untold stress on the victims, who have often become trapped by the offender.

"These offences are taking place all over the world at present and many of the people committing crimes are from organised crime groups abroad."

Police urged anyone who has any information, or who may be a victim, to contact officers on 101.