Clubbers were tests using new chemical sampling equipment

More than 50 officers were involved in raids codenamed Operation Condor to take DNA swabs and fingerprints.

Clubbers were also tested with new kit to see whether they had been in contact with illegal substances.

South Wales Police said the seasonal operation had targeted violent crime ahead of the summer influx of visitors.

Several other initiatives were also carried out, including a special inspection into door staff licences.

In addition, the drugs-testing equipment was used at a number of pubs and clubs.

'Without fear'

Inspector Colin Wooldridge said a series of initiatives had cut violent crime in the city by 8.5% on the same period last year, but the force still wanted to send "a clear message" to potential criminals.

He said: "The summer is coming and we are aware that there are more visitors coming to the city.

"We want everyone to be able to enjoy themselves without the fear of becoming victims of crime, not only at the beaches, but also at the city centre and anywhere in the city.

"(Operation Condor) is a stark message to criminals that everything possible is being done to curb their illegal activity."