RIYADH — Cyber gangs are active in blackmailing individuals, especially women, after dragging them into embarrassing situations with temptations of sex through social media websites, according to Saudi Interpol. It said terrorist groups are applying the tactics to mobilize funds for their operations. The Department for Combating Cyber Crimes at Public Security arrested as many as 3,100 people involved in such crimes last year. The crime included 64 cases of violating people's privacy, 608 cases of child pornography, 38 cases of defamation threats on the Internet and 33 cases of website hacking. In an announcement published on its website, the Central Office of Saudi Interpol warned people frequenting social networking sites such as Facebook against criminal gangs outside the Kingdom that exploit these sites to blackmail users. "Usually they introduce themselves on social media showing pictures of beautiful women. In the beginning the criminal would request users to accept him as a friend and later he would show photos of a good looking girl," the Interpol explained. After exchange of several text messages, these criminals would drag their victims to video chatting on Skype. They then would convince the victims to expose themselves in front of the camera. Within seconds, the user will get his or her nude picture on mail or cell phone. After that the criminal will disclose his or her identity and threaten to publish the video on the Internet or send it to relatives and friends if they fail to execute his demands. He would ask them to transfer an amount of money to his account through Western Union and would force them to make such transfers several times. "Sometimes, the gang would try to intimidate their victims by sending fake email messages as if it was sent by a security agency to indicate that the victim was charged with involvement in a criminal case. This is to put additional pressure on the victim to pay up," the Interpol said. "The gangs will also send video clips of girls previously trapped. In most cases those who blackmail girls will be men based outside the Kingdom. The gangs are composed of both men and women who are professional criminals. Their prime aim is to make money," it added. According to the agency, these gangs use their worldwide networks to trap victims as a source of easy income. It urged Saudis and expats to be cautious while dealing with strangers on social media networks as they have to safeguard their privacy and should not go after advertisements that appear on these websites. "People should not send any money to the gangs and should cut off all their contacts with them. They should also inform police about the gang by contacting the nearest police station or logging into the Interior Ministry's website," the announcement said. Meanwhile, the Department for Combating Cyber Crimes has classified 17 cases as cyber crimes. They include blackmail and defamation through the Internet, asking anyone to engage in indecent or immoral activity and threatening them to publish explicit photos on the Internet, hacking personal accounts and electronic mails and obtaining personal mails and threatening to publicize them. Last year, the department arrested 42 people for promoting fake Haj service agencies, three people for selling artifacts, 46 people for selling fake documents, 54 individuals for selling drugs and narcotics, 1,142 for selling weapons and live ammunition, 543 for involvement in human trafficking, 40 for impersonating and 487 for abusing and insulting people.