A pig's head has been left at the door of an Islamic centre in County Down in what police are treating as a hate crime.
Graffiti, painted overnight, was also spotted on the building in Newtownards, a large town close to Ards Airport.
Amnesty International condemned those responsible.
Amnesty International's Patrick Corrigan said:
"Our solidarity goes to the local Muslim community, who were the targets of this vile attack, apparently fuelled by a hatred of Islam or of Muslims. Anyone with information about the attack should contact the PSNI. This is a hate crime and must be prosecuted as such by the authorities.''
"In recent years this Islamic centre has been targeted by far-right activists."
He went on to say:
"When politicians fuel racist thinking, we should not be surprised when some people feel they have been given a license to act on their prejudices.''
"Amnesty calls on Northern Ireland's political representatives to do all in their power to stand against hate and to ensure all minority communities feel welcome and able to live free from fear."