It happened in the Clanmorris Close area of Bangor yesterday afternoon, Wednesday, March, 9.
At around 4pm, two young girls were approached by a man who asked them to go into an entryway with him to keep watch while he went to the toilet.
The children refused to go into the entry with the man. Neither child was physically touched during the incident.
Detective Inspector Harry Colgan said: “ The man was described as being aged in his early 20’s, of medium build, around 5’10” tall with brown scruffy sideburns.
“He was wearing a baggy black hooded top with the hood up, baggy black tracksuit bottoms and a peaked cap which was possibly grey or white in colour.
“We are investigating a link between this latest incident and similar incidents towards the end of February in the Kilocooley estate area in which a number of young children were approached.
“We are keen to identify this man immediately.
“I would appeal to anyone who noticed a man matching this description in the Clanmorris Close area today or anyone who has any information which could assist us with our enquiries to contact detectives in Bangor on 101.
“Information can also be given anonymously through the independent charity Crimestoppers on 0800 555 111.”