Police commando units search for bombs in Seoul City Hall, Jung District, Seoul, June 14. Yonhap

Police have launched an investigation after emails threatening to detonate bombs were sent to over 100 public institutions Friday, but no evidence of any explosive devices was detected, officials said.

Police received a report of the email from an employee at the lost and found center at Incheon International Airport at around 9:34 a.m., and the email's recipients included about 100 public institutions, according to the National Police Agency.

Airport police sent commandos to search the airport, but no explosives have been found. Searches were also conducted of other places, such as Pusan National University, Pusan National University Hospital and Ulsan University Hospital, but no dangerous items have been found.

Police suspect the threat is likely to be a hoax and are tracking down the sender of the email. Similar emailed bomb threats have also been sent to India in January and May this year, according to officials. (Yonhap)