Football fans and human rights groups have taken part in a protest against the use of facial recognition technology in Cardiff during the South Wales derby.
Police used the surveillance technology last October at another match between the two sides, attracting protests from fans.
''I think we're all being treated as criminals,'' one masked protester said.
Campaign group Big Brother Watch described the surveillance technology as ''a waste of public money.''
South Wales Police defended their use of the technology, saying it is being used to keep fans safe.