Police believe a petrol bomb sparked a hotel blaze from which a porter had to be pulled to safety.
The staff member was rescued from an upstairs bedroom in the Carlton Hotel, Belleek during the early hours of yesterday.
A petrol bomb was thrown through a window of the property at Main Street in the Co Fermanagh village.
Firefighters in two appliances from Belleek and nearby Enniskillen were called to the scene just before 1.30am.
The fire was contained within the downstairs lounge area of the property. The porter was uninjured.
Police said they were treating the blaze as arson.
"A window in the property was smashed and what is believed to be a petrol bomb thrown inside. Police and the Northern Ireland Fire and Rescue Service (NIFRS) attended and the fire was extinguished.
"Nobody was injured in the incident," said a PSNI spokesman.
It is understood the emergency services were alerted by a passer-by.
"Fire crews rescued a night porter from an upstairs room. He was uninjured. The fire is believed to have been started deliberately," an NIFRS spokeswoman said.
Phil Flanagan, Sinn Fein MLA for Fermanagh and a former employee of the Carlton, described the attack as an outrageous act of vandalism.
"I would condemn it in the strongest possible terms," he added.
"The Carlton Hotel is of major economic importance in the Belleek area. Those behind acts of this sort have very little to offer our society.
"Thankfully the prompt response of the local fire service personnel ensured that any damage was minimised and we are all very grateful to them for that."