Seoul, Jul 10 (IANS): The number of unregistered baby cases under police investigation in South Korea has increased to 939, as a nationwide campaign is under way to confirm the well-being of more than 2,000 undocumented babies born since 2015, the National Office of Investigation said on Monday.

A total of 1,069 "ghost baby" cases had been reported to police as July 7, and 939 of them are currently under investigation, the Office said.

The latest figure marks an increase of 159 additional cases under investigation since the tally on July 6, reports Yonhap News Agency.

Of the total cases filed, 34 babies have been confirmed dead, 19 of which had no signs of foul play.

Police investigations are under way into suspected crimes involving 11 other dead babies, including two deaths reported in Seoul.

Four other cases were referred to the prosecution after police found criminal suspicions involving their parents in the deaths of the newborns.

The police said they are focused on finding the whereabouts of 782 undocumented babies.

Police have been expanding their probe into cases of undocumented babies who have medical records of birth but no official birth registration, and the government is conducting a nationwide campaign to check the well-being of more than 2,000 unregistered babies.