In a weekend of mayhem, El Salvador's murder rate doubled in a 24-hour period, police said Monday, emphasizing the increasing role played by the Maras youth gangs, dpa reported. Eighteen people were killed with guns, and the other victims died of wounds from knives and other sharp objects. Maras, the youth gangs blamed for much of the upswing in violence, were founded two decades ago in the Los Angeles neighbourhoods settled by immigrants from Central America. The gang structure and rituals were copied by Maras who returned home to the large cities of Central America. Last month, the Organization of American States for the first time officially tackled the issue. The gang members, whose bodies are frequently covered with tattoos, engage in senseless violence like the decapitation of victims, especially rival gang members. Guatemala alone has an estimated 200,000 Mareos, as the members of the gangs are known. --SP 2226 Local Time 1926 GMT