Galway's City Hall has been damaged in an explosion which occurred shortly before 8am this morning.
Gardaí said a number of staff were in the building at the time of the incident but there are no reports of injuries.
A Garda spokesman said a number of windows had been blown out in the explosion but reported that damage "did not seem to be extensive."
The cause of the explosion has not yet been established but Bord Gáis denied reports that it may have been gas related. The company said Galway City Hall is not served by natural gas.
The building is currently closed to the public and forensic investigators are on their way to the scene.
Galway City mayor Declan McDonnell said he was relieved that so few people were in the building when the incident took place.
"If this had happened an hour or two later there would have been serious consequences, about 300 to 400 staff based there," he said.
"There were a few people in the building at the time but nobody was in the section damaged.
"Obviously the ones that were in there are shocked and upset, but the good news is nobody was injured."
Mr McDonnell revealed that the blast happened in the payroll department and damaged half of the ground floor and blew out 15 large windows.
The administration, planning and finance sections of the council were also housed in the building, he said.
But the Mayor stressed that services remained in operation across the city.
"There is an emergency team meeting this morning, putting in place plans for a new switchboard in one of our other premises for the time being," he added.
"The building will be out of commission for a few weeks so the staff who work where will work from other buildings."
Additional reporting: PA