Rescuers have spent most of the day searching for a small aircraft reported crashed in the North.
A large part of Co Fermanagh was combed by helicopters, mountain rescuers, police and firefighters after the alert was raised this morning.
So far there have been no reports of any aircraft missing or overdue. St Angelo Airport near Enniskillen is understood to have received the original call.
As well as a reported sighting, several local people said they heard a loud bang in the area at around 10am.
A police spokesman said: “The search operation has been declared a major incident by police, who have brought in support units from outside the area to join local officers and local firefighters in the search.
“Police are appealing for anyone involved in flying activities to check among themselves to see that all are accounted for.”
The hunt was covering a wide area from Enniskillen northwards to Belleek and from Lower Lough Erne westwards to the border with the Republic of Ireland. The accident was reported at around 10am today in the Boho area.
A police helicopter was joined by a Coastguard helicopter based in Sligo and searches on the ground and in local lakes continued.
Earlier a fire service spokeswoman said: “Police are co-ordinating the search and we have five crews assisting.
“There was a report that an aircraft came down.”
The Northern Ireland Ambulance Service sent out a rapid response vehicle but was unable to find anything, a spokesman said.
The effort was hampered by poor weather and visibility conditions.