Two people have been taken to hospital after an incident at Lough Enagh in Co Derry.
The Northern Ireland Ambulance Service said it received an emergency call shortly before 6.30pm.
A rapid response paramedic, five emergency crews, a hazardous area response team and an ambulance officer were dispatched to the scene.
NIAS also tasked the air ambulance to attend the incident.
A spokesperson said: "This remains an ongoing incident as we work with partner agencies, including PSNI, NIFRS (Northern Ireland Fire & Rescue Service) and Foyle Rescue, at the scene.
"So far two patients have been taken by ambulance to Altnagelvin Area Hospital."
The PSNI said it was dealing with an incident in the Temple Road area of Derry.
It asked members of the public to avoid the area as it dealt with the situation.
