PSNI Assistant Chief Constable Mark Hamilton said: "I can confirm that a third teenager has now sadly died from injuries sustained during an incident at the Greenvale Hotel in Cookstown last night.
The three teenagers who died are a 17-year-old girl, a 17-year-old boy and a 16-year-old boy. A 16-year-old girl is in a stable condition in hospital. A further two teenagers were treated for injuries they received during the incident.
First and foremost my thoughts this morning are very much with the families of the three young people who passed away and those who were injured. It is heart-breaking that an event which should have been fun for these youngsters on St Patrick’s night should end in such a terrible tragedy.
Detectives have now launched an investigation in conjunction with Environmental Health at Mid Ulster Council to try and establish what happened.
Events unfolded shortly before 9.30pm last night when the Northern Ireland Ambulance Service received a 999 call with reports of people injured outside the hotel. They declared it a major incident and police, Fire Service and Environmental Health then also attended the scene.
Police arrived within two minutes of the call form the Ambulance Service and quickly secured the scene. We made an urgent appeal via social media to parents of the young people to come and collect them from a Friends and Family Centre which was established in the nearby Glenavon Hotel.
Our investigation is at an early stage, and while the exact cause of the incident is still unknown, there are reports of a crush at the scene and initial enquiries indicate that a large group of young people were waiting to enter a disco. We also have reports of some fighting after the incident commenced and at least one person has reported that they were assaulted.
We are continuing to interview people who were there to establish the full facts and I would appeal to anyone who witnessed what happened to contact police on 101 ext 52014. We need parents to talk to their children this morning and encourage them to come and tell us what happened. Please do not post photographs or videos online. Please share them with the PSNI. I would also ask motorists who have dash cam footage, as well as anyone who captured the incident on their mobile phone through photographs or video, to upload them to Major Incident Public Portal https://mipp.police.uk/