Firefighters from Donegal are assisting their counterparts across the border after a large blaze broke out at the premises of a coffin maker in Strabane.
It is believed a lightning strike hit the building in the Railway Road area of the town.
The area has been cordoned off and firefighters are currently tackling the blaze.
The PSNI are advising the public to avoid the area to allow emergency services to deal with the blaze.
Eyewitnesses in the area reported lightning immediately before the fire.
The UK Met Office had earlier issued a weather warning for the six counties in Northern Ireland.
It warned of frequent lightning, heavy rain, and hail showers that “could cause damage to property and travel disruption”.
Met Éireann had also issued a thunderstorm warning for several counties across the northwest, including Donegal.