The chairman of a youth football club has said he is concerned after some players were allegedly approached online by a man posing as a 14-year-old girl.
Some of the players are members of St Patrick's Football Club in the New Lodge in north Belfast.
Chairman Patrick Downey has said he is "devastated" by what has happened.
On Wednesday the club posted details on Facebook of the alleged online grooming, saying the children were contacted through social media and asked for inappropriate photos.
The club's members are boys and girls aged from four to 17 years old.
Mr Downey said club officials were contacted on Wednesday morning by a concerned parent, who told them officers from the National Crime Agency had arrived at their door to inform them their son had been a victim of online grooming.
"This was very concerning for us," the chairman said.
"We spoke to the child. We spoke to the officers, who informed us that there were other children involved in our football club who had also been approached.
"They also told us that there were lots of other kids in and around the Belfast area - some in other football clubs, some in other walks of life - who had all been contacted through their own personal Facebook and Instagram accounts."
The football club is holding an emergency meeting Thursday evening for coaches and committee members to address what has happened.
The club has also invited the Police Service of Northern Ireland and the National Society for the Prevention of Cruelty to Children (NSPCC) to come and speak to children and their parents about online safety.
Eddie Burns has a son and daughter who attend the club. While they were not targeted, he said it was a worrying development.
"Although this didn't come to my personal doorstep, it came to the doorstep of the club and to think that there are predators out there targeting children within our community.
"You always hear about it and you're always warned about it and you see the warnings but you never ever think it's going to come knocking on your door and unfortunately it came within this area.
"My children aren't on social media at all. I'm one of these parents that believes that they're still too young. They're still babies. Social media, it's a big scary world out there.
"We need educated ourselves. It's all well and good educating the children, but if we're still their guardians and still their parents, it's up to us. It falls on our doorstep as well. We have to protect them and we need to know how to protect them."
On Wednesday, the National Crime Agency confirmed a man was arrested in England as part of this investigation. He has since been released on bail while the investigation is ongoing.
Officers from the PSNI's Child Internet Protection Team are providing assistance to officers from the NCA as they continue their inquiries.