An anti-war demonstration by peace campaigners who want a defence company in Brighton to close was held in the Sussex city on Saturday.
The protesters were stopped from marching into the city centre
Protesters from the Smash EDO group claim EDO MBM Technology manufactured components for weapons used in the war against Iraq.
They believe the conflict was illegal and want the firm's directors arrested and put on trial as war criminals.
Police officers were deployed to stop marchers from entering the city centre.
Some of the protesters claimed there were too many officers for the number of demonstrators present, and that they had felt intimidated.
The protest took place when the city was packed with shoppers
They were also dismayed that they had been prevented from moving down Queen's Road.
However, Supt Kevin Moore, from Sussex Police, said the demonstration had been handled reasonably and demonstrators had been allowed to conduct their protest in a peaceful way.
"It has always been our intention to facilitate lawful and peaceful protest, but the lack of co-operation meant closure and disruption of the main roads when the city centre was packed with Saturday afternoon shoppers, which is unacceptable," he said.
Police said they would consider the allegations made against EDO MBM Technology.