MEXICO CITY, June 21 (Reuters) - Mexican President Andres Manuel Lopez Obrador on Monday called for a federal investigation into a spate of deadly gun violence in the border city of Reynosa over the weekend, calling the victims "innocent people." Lopez Obrador, speaking at a regular news conference, said he would direct the attorney general"s office to investigate the string of shootings that killed more than a dozen people. "Everything indicates that it was not a confrontation, but it was a command to shoot people who were planned to be confronted," Lopez Obrador said. "It is a cowardly attack that took the lives of innocent people." Armed gunmen fired from cars during multiple attacks in several neighborhoods of Reynosa on Saturday, said state security forces, which includes the police and military. read more Lopez Obrador said 14 people were among the victims, though state security forces said later on Monday that 15 civilians were killed, including one who died in the hospital. Four other people believed to be from a criminal group were killed in clashes with police. The multiple shooting incidents on Saturday were committed by "individuals who were aboard several vehicles," the security forces said in a statement. Reynosa, which borders Texas, is one of Mexico"s most violent cities and is a battleground for powerful drug gangs fighting for control.