|Clinton is visiting Mexico - her scond in less than a year - for meetings on border security and drug trafficking [AFP]
Armed men have killed seven people at a park that had been built as an anti-violence measure in the besieged Mexican border city of Ciudad Juarez, authorities say.
The attackers arrived during a football game in a park in the Francisco I Madero neighbourhood and opened fire, Carlos Gonzalez, a spokesman for the Chihuahua state prosecutors' office, said on Monday.
Two of the people killed had been playing football.
Four people, including a 12-year-old girl, were hospitalised in critical condition, and one later died of his wounds.
Investigators found 180 bullet casings from the sort of assault weapons typically used by drug gangs, Gonzalez said, though they had not yet identified the perpetrators or a motive.
Three other people, two men and a 15-year-old boy, were killed on a street in the same neighbourhood on Monday, although Gonzalez said there was no evidence that the attacks were related.
Ciudad Juarez, across the border from El Paso, Texas, is Mexico's most violent city, with more than 3,000 killed last year as the Sinaloa and Juarez drug cartels vie for control of lucrative trafficking routes into the US.
More than 34,600 people have been killed nationwide since Felipe Calderon, the Mexican president, launched a crackdown against drug traffickers in December 2006.
Against this backdrop, the US secretary of state, in her second visit to Mexico in less than a year, offered strong on Monday support for Calderon's war on narcotics traffickers.
"The drug traffickers are not going to give up without a terrible fight," Hillary Clinton said at a news conference with Patricia Espinosa, Mexico's foreign minister, in the central city of Guanajuato.
"When they do things that are just barbaric, like beheading people, it is meant to intimidate," she said.
Clinton said Calderon had no choice but to confront them: "It is hard. It carries all kinds of costs. But there is no alternative."
The Mexican government says the bloodshed is a sign the gangs are weakening. But rampant killings, including grenade attacks and decapitations, are spreading across Mexico and beginning to scare international investors.
Clinton pointed to the killing and capture of more than two dozen top cartel capos as a sign of Calderon's success.
But in a leaked cable from 2009 published by the Spanish newspaper El Pais, US embassy officials said: "Calderon's security strategy lacks an effective intelligence apparatus to produce high-quality information and targeted operations."
The cable described the Mexican government's intelligence apparatus as "fractured, ad hoc, and reliant on US support."
Clinton said she could not comment on the alleged state department documents released on the internet.