Gunmen have entered a downtown bar in the northern Mexican city of Monterrey and shot 20 people dead

A preliminary investigation suggests that the attack was sparked by a dispute between organized crime groups for control of the El Sabino Gordo nightclub, where drugs are sold, said Jorge Domene Zambrano, a public safety spokesman. In addition to the 20 dead, five others were wounded and taken to the hospital. The attack was likely the work of a rival gang. Many of the dead were employees of the nightclub.