(Adds shootout details, threats against police, paragraphs 10-13) By Lizbeth Diaz TIJUANA, Mexico, Jan 17 (Reuters) - Hitmen from Mexico's drug gangs are breaking traditional codes of honor by killing children in a chilling new chapter of a narcotics war that President Felipe Calderon is struggling to control. In unprecedented attacks, gunmen killed a 3-year-old boy and a 9-year-old girl and seriously wounded a 12-year-old girl in the city of Tijuana on the U.S. border this week as they targeted a senior local police officer. Even hardened residents of Tijuana, where more than 300 people were killed in drug violence last year and severed heads were dumped on city streets, were shocked by photos of young Jose Luis Ortiz's body riddled with bullets. "How much longer must we wait for results from the military? Now the narcos are killing our children," said a Tijuana shop assistant who gave her name only as Fernanda. Ortiz and his mother and father were shot dead as they slept on Monday night. Gunmen apparently mistook the boy's father for a police officer and had no qualms about killing the 3-year-old. Moments later, they found the police officer they were looking for and murdered him, his wife and their youngest daughter. Their other child was wounded. "This is a new strategy to attack children and families and respond to the government's military assault on the cartels. The gangs want to sow panic and fear to overwhelm the authorities," said Victor Clark, a drug trade expert at San Diego State University. Over the past three decades, Mexican drug cartels hauling cocaine north to the United States have generally held to a code of honor that bans killing women and children and stops them from becoming addicted to the drugs they traffic. But as the cartels feud over smuggling routes and fight troops and federal police trying to crush them, violence has escalated and many traffickers are now addicts. BATTLE OUTSIDE KINDERGARTEN On Thursday, gunmen and more than 100 police and soldiers fought a three-hour battle outside a kindergarten in central Tijuana in which one hitman died and two police officers were seriously wounded, Red Cross officials said. Dozens of children were evacuated from the kindergarten, many carried by masked soldiers. Police said they arrested several people, including a man they believe is a top assassin working for the Tijuana cartel, known also as the Arellano Felix gang. Gunmen also dumped three headless pigeons stuffed with money outside police headquarters in Tijuana's neighboring beach town of Rosarito -- a macabre warning of more violence. "We know this is a war and we have to win it every day," Baja California's state governor, Jose Guadalupe Osuna, said after the Tijuana killings. Mexico's main drug struggle is between the Gulf Cartel on the eastern coast and an alliance headed by Joaquin "Shorty" Guzman, a jail escapee and Mexico's most wanted man. Calderon has made crushing the drug cartels a priority since taking office a year ago, sending 25,000 soldiers and police to attack the gangs. A main focus of the campaign has been Baja California, Mexico's deadliest state last year with more than 400 drug-related murders. In January, hundreds of police and soldiers rolled into Tijuana and Rosarito to reinforce an already large troop contingent, but the shootouts continue. Baja California officials and Attorney General Eduardo Medina Mora this week promised a redoubling of efforts to stop the violence, but some officials are pessimistic. "The corruption among the state's police forces runs so deep that it is impeding our work," Gen. Sergio Aponte, joint head of military operations in Baja California, told Reuters. "There are many police officers who have dedicated themselves to protecting criminal interests." (Writing by Robin Emmott; Editing by John O'Callaghan)
A policeman carries a child away during a gun battle in Tijuana, in Mexico's state of Baja California, January 17, 2008. A shootout on Thursday, after police agents moved in on ...
