Security at D-Day commemorations taking place at Southsea Common in Hampshire this week is the "largest operation" ever undertaken by Hampshire Constabulary, police have said.
An anniversary ceremony is taking place on Wednesday to remember 75 years since allied forces landed in Normandy during World War Two.
Veterans are being invited as honoured guests of the ceremony.
American President Donald Trump will be there, part of his three-day state visit to the UK, along with the Queen and outgoing Prime Minister Theresa May.
Security measures have been put in place ahead of the celebrations, including vehicle barriers, security fencing and police patrols of armed and unarmed officers.
Hampshire Police has said the public can also expect to see marine units on patrol and officers on horseback.
David Hardcastle, Assistant Chief Constable of Operations at Hampshire Police says: "At the moment there is nothing to suggest there is a direct threat to this event. The security measures we're putting in place are proportionate to the threat we face as a country, but also on this scale and complexity."
More than 130 police search officers are being deployed over three days to patrol the area in the run-up to the event.
Police have been planning operations for the last eight weeks, with the final few spent monitoring "what is going in and out" of Southsea Common.
Hampshire Police did not say how much policing the event is costing, suggesting a more definite figure can be determined after the event has happened.
Despite heightened security and extra personnel, police are urging local residents to help make the event safe, encouraging residents to alert police if they see anything suspicious.
The advice if you're coming to the event is to "plan your journey and arrive early".