Law enforcement officials are urging parents to pay more attention to their children's activities online because of an increase in sextortion cases.FBI agents and Nashua police said Friday they have seen an increase in sextortion cases across a variety of social media platforms. Nationally, the FBI said cases increasingly target boys between the ages of 14 and 17, but in New Hampshire, the commander of the Internet Crimes Against Children Task Force said there is a difference."It's pretty balanced, more or less," said ICAC commander Eric Kinsman. "We're seeing victims are both male and female."Sextortion involves a predator often posing as a young person to get a child to send them pictures that are sexual in nature. Blackmail then follows."If they don't send them money or some type of gifts, then they will use that image to cause either physical or mental harm," Kinsman said.He said the actual number of cases is higher than reported because many victims are ashamed to admit what they've done. But Kinsman said with more than 100 agencies in the state making up ICAC, help is available."We put 100% effort forward in terms of investigating these crimes and see if we can identify a suspect on the other end of it," he said.The FBI has tips for staying safe online, including blocking or ignoring messages from strangers and being suspicious if someone you met on a game asks you to start talking on a different platform.Kinsman parents need to be aware of what their children are doing online."Just simply pay attention," he said. "You know your kid best. Don't be afraid to have that conversation."FBI officials said that if a case of sextortion is suspected, nothing should be deleted until law enforcement is able to review it.