Police have been on patrol at Larne Harbour in a bid to reassure passengers.
Patrols have been stepped up in Mid and East Antrim and across Northern Ireland in response to an increased terrorist threat following Monday night’s bomb attack at Manchester Arena in which 22 people were killed and 59 injured.
PSNI Chief Constable George Hamilton said that the government’s decision to raise the terror threat level to “critical” also applies to Northern Ireland.
The PSNI said that there have been “reassurances patrols” at Larne Harbour.
Officers from Carrickfergus covered 160 miles across Mid and East Antrim yesterday (Thursday).