A bomb was detonated outside the City of Culture office in Derry, Northern Ireland on Wednesday night, police said.
Northern Ireland police report that there are not aware of any injuries and that the buildings have only sustained minor damage.
It is the second time that the office has been targeted after a pipe bomb planted by dissident republicans caused damage to the buildings.
Witnesses to the latest bomb said that it was a large blast that left smoke billowing out of the building.
A warning with a recognised codeword is thought to have been given around 22:00 BST - less than an hour before the bomb detonated in Guildhall Square.
"Thankfully no-one has been injured but those graces are no thanks to those who are behind this attack," said Foyle MP Mark Durkan said.
"They are out to destroy and they don't care if they injure or kill when they are at it.
"Derry is a city with many challenges and with many difficulties. But the City of Culture is one of the opportunities we have."
East Londonderry MP Gregory Campbell also condemned the bombing.
"These people are merely trying to do what others have tried for 30 years before them, and failed," Mr Campbell said.
"They simply do not get the picture, it doesn't matter how many times they try they will repeatedly fail as their predecessors in the Provisional IRA did before them."