Police investigated a record 1,813 cases involving minors who fell victim to sexual and other crimes perpetrated through the use of social media in 2017, official data showed Thursday.

The figure, which excludes cases involving online dating services, is believed to have been pushed up by an increasing number of children who are coerced into sending naked photos of themselves to people they met online, according to police.

The number of such cases was up 77 from a year earlier to the highest level since comparable data became available, in 2008, the National Police Agency said.