A significant increase in juvenile offenders involved in so-called special fraud cases inflicted ¥17.49 billion in financial damage in the first half of 2018, National Police Agency data showed Thursday, although financial losses stemming from such cases dropped for the fourth consecutive year over the January-June period.

Special fraud cases include phoning seniors and asking for money while impersonating their children and the issuance of false contracts.

Although the figure dropped ¥1.33 billion from a year earlier, the level remains "extremely serious," an NPA official said, noting that the data saw a roughly twofold increase in the number of juveniles age between 14 and 19 implicated in the crimes.