The Coahuila law officesaid gunmen loaded in five cars fired at the crowd and more than 200shells of AK-47 machine guns, a favourite weapon of drug gangs, werefound scattered at the scene.
Mexican officialssaid the death toll could increase as a number of the injured are in acritical condition.
Most of the victims arebetween 20 and 38 years old, they said.
The causefor the crime has not yet been determined and investigations areunderway.
It was considered a bloodshed week inMexico as the number of people killed in offences reached 50, mostlyin northern states.
Although the MexicanGovernment has deployed some 50,000 soldiers to supress gangsters oforganised or drug-related crime since December, 2006, the number ofarmed attacks has continued to rise, taking more than 24,000 lives./.