Black Friday sales at Tesco put 'pressure' on police
A senior police officer said he is "disappointed" the force had to use its limited resources to deal with clashes at Tesco caused by Black Friday sales.
South Wales Police Deputy Chief Constable Matt Jukes said officers will speak to supermarket managers to try to stop it happening again.
Officers were called to four stores in Cardiff, Bridgend and Merthyr Tydfil.
DCC Jukes said he is "disappointed that these stores did not have sufficient security staff to manage events".
Staff called for help at the Tesco Extra store in Gabalfa, Cardiff, concerned about the number of people who had turned up for the sale events.
Some shoppers tweeted there had been fights, but police said any incidents had dispersed before they arrived.
No arrests were made.
DCC Jukes added: "Police resources are already stretched in the early hours of the morning and the events that took place put even more pressure on our service to the whole community."
All calls came in just after midnight when stores opened. Officers were needed for crowd control.
Customers at the Gabalfa store began queuing at 18:00 GMT on Thursday to enter the supermarket at midnight.
One customer, John Swan, got there at 23:00 GMT and left empty handed 90 minutes later.
He said: "I was shocked to be honest, me and my partner have never been before so we went to have a look. It was chaotic.
"The manager said a couple of minutes before the deadline 'no-one is to shove or to push and anyone pushing or shoving will be ejected from the store'.
"He was totally ignored."
A Tesco spokesman said it contacted police about the Cardiff store "in the interests of customer safety".
"We're grateful to the police for their support and the store is now trading normally," they added.
Black Friday has become known for altercations and arguments between shoppers as they fight to lay claim to items on sale in the weeks before Christmas.
The events have been adopted in the UK following the traditional sales in the US following the Thanksgiving Day holiday.