A number of homes in Londonderry have been evacuated because of a gas leak.
The leak was discovered in Dove Gardens, in the Bogside area of the city, a few hours after an arson attack.
Fire fighters dealt with a car fire which then spread to a mid-terrace house shortly after 05:00 BST on Tuesday.
A man in his 40s has been treated for burns. It is believed he was trying to move the car when he was injured.
The Northern Ireland Fire and Rescue Service (NIFRS) is working to establish the cause of the gas leak.
"We have a leak in one of the houses here at Dove Gardens, it's coming out of a medium pressure gas mains," said NIFRS Assistant Group Commander Kevin Lynch.
"We have engineers on site and we are working along with them to try and find the leak and get it stopped.
"We have evacuated five homes in the street just as a safety precaution."
Sinn Féin Councillor Kevin Campbell said it could have been a "very serious incident" had the fire spread.
"I would like to commend the quick actions of the car owner in his efforts to stop the fire from spreading further despite the dangers he faced," he said.
"It must have been a very frightening experience."
Police, who also attended the scene, told the BBC that their enquiries were ongoing.