A bomb scare hit a University when two bags containing underwear and cake were discovered with a message that promised of an explosion if opened.

Police evacuated Kyushu University's pharmacology department in southern Japan early Tuesday and called in the bomb squad after a staff member found a white paper bag with the warning.

Later officials were told that two female students of the department brought the packages into the building as a birthday present for a friend and they wrote the note because they thought it would stop anyone from touching the bags.

They left them in the mail room Monday night, emailing their friend to tell her to collect them. The friend, however, forgot.

The police spokesman it was too early to say if they would be charged.