One of Mexico’s most feared drug cartels has been brought to its knees in the US after a sweep of 755 arrests — 52 of them this week — according to Barack Obama’s new Attorney-General.

Eric Holder, appointed America’s law chief three weeks ago, said federal agents would continue their crackdown on Mexico’s cocaine, marijuana, Ecstasy and methamphetamine trade until all of the country’s ruthless and politically connected smuggling organisations were wiped out.

Within hours of the announcement, Mexico said that it was sending another 5,000 troops into the lawless border town of Ciudad Juárez, where 250 people have been murdered by cartel hitmen this month alone, and where a recent emergency meeting of top-level Cabinet ministers was disrupted by a bomb scare. Juárez is located directly across the border from El Paso, Texas.

Critics argue that by waging war against the cartels the US is simply raising the price of narcotics — thus making the trade more lucrative and exacerbating the violent competition over smuggling routes. Nevertheless, the Justice Department said that it remained confident that its strategy would continue to produce results.

“These cartels will be destroyed,” Mr Holder told a press conference on Wednesday when he revealed the details of Operation Xcellerator, launched in 2007 and aimed primarily at Mexico’s Sinaloa cartel. “They are a national security threat,” he said of the group, based in the northwestern state of the same name. “They are lucrative. They are violent. And they are operated with stunning planning and precision.”

The Sinaloans were blamed for provoking a turf war in 2005 when they tried to take over territory in northeastern Mexico controlled by the rival Gulf cartel. The effort failed and the Sinaloans later split into two factions. One is headed by Joaquín “Shorty” Guzmán — Mexico’s most wanted criminal — and the other by his former enforcers, the Beltrán Leyva brothers.

When Mexico’s President Calderón came to power two years ago he tried to stop the turf war with a massive military intervention but this ultimately only worsened the violence.

Eduardo Medina Mora, the Mexican Attorney-General, said yesterday that his country had spent $6.5 billion over the past two years fighting drug gangs who have a combined annual turnover of $10 billion. Over 1,000 people had been killed in drug violence so far this year, he added.

Many poor Mexicans turned to petty crime to support themselves as they lost their jobs with the cartels, resulting in a nationwide spate of robberies and kidnappings. More than 6,000 Mexicans were killed as a result of the chaos last year, with the cartels using everything from political assassinations to beheadings and acid baths to terrorise and intimidate their rivals.The dumping of headless or tongue-less corpses, sometimes near tourist resorts, or in one case next to a school playground, has become almost a daily occurrence. The US intensified its own campaign against the cartels when the violence began to spill over into cities such as Phoenix, Arizona.

Since Operation Xcellerator began, about 70 distribution hubs and cells across 26 US states have been shut down, resulting in the seizure of 12,000kg of cocaine, 7,250kg of marijuana, 544kg of methamphetamine and 1.3 million Ecstasy pills.

US cocaine prices have more than doubled while purity has fallen by more than a third — both measures of the drug’s increasing scarcity. Methamphetamine prices have also risen.

The Americans and the Mexicans have been astonished by the wealth and the sophistication of the cartels which, in many cases, have access to the very latest in military-grade weaponry, including .50-calibre heavy machineguns, anti-tank rockets, grenade launchers and mortars.

In many cases police forces within Mexico must become subsidiaries of a cartel or face annihilation. Many Mexicans blame this state of affairs on the US: it is Americans who buy the drugs, they say, and thus give the cartels money. It is Americans they blame for the “iron river” of arms that flows south of the border, where gun-control laws are much stricter.

According to a recent investigation by The New York Times, there are 6,600 licensed gun dealers on the northern side of the US/Mexico border, many of them operating out of their own homes.

“We can move against the most outrageous purveyors of arms to Mexico but the characteristic of the arms trade is it’s a parade of ants — it’s not any one big dealer, it’s lots of individuals,” the attorney-general of Arizona, Terry Goddard, said. “That makes it very hard to detect because it’s often below the radar.”

It is partly in response to such concerns that Washington has pledged $1.6 billion in equipment and training assistance to Mexico over the next three years to address the problem.

Mr Holder has said also that the Obama Administration will push for renewing a ban on assault rifles. “I think that will have a positive impact in Mexico,” he said. The ban was enacted under President Clinton but expired during the Bush Administration amid heavy pressure from American gun-rights advocates.

Lords of cocaine

— The Mexican Government has identified seven drug cartels operating in the country, the biggest ones being Gulf, Sinaloa, Juárez and Tijuana. Several work together within an alliance called “the Federation”

— The cartels have been linked to human and arms trafficking, car theft and kidnapping

— Cartel bosses employ individuals and gangs of enforcers, known as sicarios. The Gulf and Sinaloa cartels have highly organised groups working for them, respectively, the Zetas and Negros. The Zetas are effectively a private army, with many members having deserted from the Mexican paramilitary

— Mexico's cartels have become more powerful since the demise of Colombia's Cali and Medellín cartels in the 1990s

— President Calderón has said drug violence is a threat to the Mexican state. Since taking office in December 2006 he has sent 24,000 soldiers and federal police to nine states to combat the cartels

— Mexico's most wanted fugitive is Joaquín “Shorty” Guzmán, head of the Sinaloa cartel

— In 2008 5,800 died in Mexican drug wars

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