More than 600 people have been stopped and spoken to by police - and some of them searched - during the Labour Party conference in Brighton.
Armed officers patrol Brighton city centre as part of conference security
Sussex Police said on Thursday that officers' stop and search powers were a vital deterrent to terrorism.
The police statement was issued after suggestions that officers had been "heavy-handed", the force said.
A spokeswoman said many people in the city said "they wanted police to use these powers to keep them safe".
She said that policing the conference had been "the largest counter-terrorism operation" the force had run, involving hundreds of police officers and other staff.
"As part of that operation police have been given power under the Terrorism Act to stop and search people," she said.
"This power does not require any suspicion and is used to detect and deter acts relevant to terrorism."
She said that the way officers spoke to and interacted with people as they were being stopped was "of utmost importance".
"By definition, many totally innocent people going about their normal lawful business will be stopped and checked," she said.
"This is what creates the deterrent for terrorists."
Ring of steel
The £3.7m security operation saw a "secure island site" established round the Brighton Centre.
The neighbouring Grand Hotel and Hilton Metropole were included in the seafront ring of steel, and concrete slabs were laid to prevent terrorist attacks.
Sussex Police said conference security was reviewed after July's London bombs.
The concrete slabs around the island site were to prevent attacks such as truck or car bombs.
Armed checkpoints were also set up at various points leading into the
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