By Julian Cardona
CIUDAD JUAREZ, Mexico (Reuters) - The killing of three people linked to the U.S. consulate in Mexico's bloodiest drug war hotspot has thrown President Felipe Calderon a major test as he heads to this border city on Tuesday to try to contain spiraling violence.
Suspected drug hitmen killed an American woman working at the consulate in Ciudad Juarez, just over the border from El Paso, Texas, and her U.S. husband on Saturday as they left a children's birthday party. A Mexican man married to another consulate employee was killed around the same time in another part of the city after he and his wife left the same event.
The FBI joined Mexican authorities in the investigation of the murders, while U.S. officials downplayed suggestions that U.S. diplomats had been targeted in the attacks.
The White House expressed outrage over the murders and pledged to continue supporting Mexico's fight against ruthless gangs smuggling narcotics into the United States.
"The tragic murders over the weekend underscore the imperative of our continued commitment to work closely with Mexican authorities to take down the drug trafficking organizations," National Security Council spokesman Mike Hammer.
Violence has exploded in recent months in Ciudad Juarez as rival drug gangs struggle for control over the city, a hotspot in Mexico's three-year-old drug war.
The deployment of thousands of troops by Calderon, who has staked his presidency on beating back the drug cartels, has failed to stop the killing of more than 4,600 people over two years in the Ciudad Juarez area.
Calderon was already scheduled to visit Ciudad Juarez before the consulate murders added to outrage at the slaying in January of 15 people, mainly teenagers, at a party.
Many residents blame Calderon for fanning violence that has provoked an exodus of people from the manufacturing city and forced some U.S. companies to freeze investment in factories.
"Calderon's strategy is not working, but he doesn't want to change it. He believes in the military and so we are at this impasse," said security expert Pedro de la Cruz at the National Autonomous University of Mexico. "We are going to witness a lot more murders for the time being," he added.
NO EVIDENCE CONSULATE TARGETED
An FBI official in El Paso said there was still no evidence the consular killings were drug-related. "There is no information that indicates that the victims were directly targeted due to their employment at the consulate," said FBI Special Agent Andrea Simmons.
Deeply concerned about the violence, Washington is spending hundreds of millions of dollars to help train Mexican police and provide helicopters and equipment to fight drug gangs.
But across Mexico, drug violence is at its worst level ever. Nearly 19,000 people have been killed since Calderon came to power in 2006, and many U.S. students have heeded warnings not to cross the border this year for their annual "spring break" vacation.
Mexican anti-drug officials defend the army-backed strategy and told Reuters that the focus remained on using the 8,000 troops and federal police on the streets of Ciudad Juarez to crush drug cartels. Calderon is expected to meet the U.S. consul in Ciudad Juarez on Tuesday and try to reassure local residents he is fighting the violence, but little more.
Bloodshed has exploded in Ciudad Juarez in recent months as the head of the Juarez cartel, Vicente Carrillo Fuentes, fights off an offensive by Mexico's No. 1 fugitive drug lord, Joaquin "Shorty" Guzman.
Calderon's main tactic so far has been to announce more investment in schools, hospitals, drug rehabilitation clinics and projects to regenerate the desert city. The conservative, who has made two hurried visits to Ciudad Juarez since the teenagers' murders in January, says he aims to entice youths away from the drug trade with jobs and education.
But many are skeptical as the murders continue, including the massacre of six people as they attended a funeral last week. "Ciudad Juarez is now a naked city without protection," said Arizona-based drug trade expert and author Charles Bowden, who has sources close to the Juarez cartel.
(Additional reporting by Robin Emmott in Monterrey and Michael O'Boyle in Mexico City; editing by Anthony Boadle)