THE US Drug Enforcement Administration has been transformed into a global intelligence organisation with a reach far beyond narcotics, and an eavesdropping operation so expansive it has to fend off foreign politicians who want to use it against their enemies, according to secret diplomatic cables.

The cables, from the WikiLeaks cache, reveal how drug agents balance diplomacy and law enforcement in places where it can be hard to distinguish politicians from traffickers, and where drug rings are themselves mini-states whose wealth and violence permit them to run roughshod over struggling governments.

A leaked US diplomatic cable from August 22, 2009, quotes then US ambassador to Panama Barbara Stephenson as saying the newly elected conservative President Ricardo Martinelli asked to use the agency's wire-tapping program soon after he took office on July 1.

According to the cables, Mr Martinelli demanded the DEA spy on leftist politicians he believed were plotting to kill him. ''I need help with tapping phones,'' he wrote. The US, according to the cables, feared Mr Martinelli, a supermarket magnate, ''made no distinction between legitimate security targets and political enemies''.

Mr Martinelli, who the cables said possessed a ''penchant for bullying and blackmail'', retaliated by proposing a law that would have ended the DEA's work with specially vetted police units. He then tried to subvert the agency's control by assigning non-vetted officers to the counter-narcotics unit. Mr Martinelli last night denied he had asked the US to install phone taps on his political opponents, but acknowledged a request for help against organised crime figures.

The cables also reveal that in Sierra Leone a cocaine-trafficking prosecution was almost upended by the attorney-general's attempt to solicit $US2.5 million in bribes. In Guinea, the biggest drug kingpin was the president's son and before police destroyed a narcotics seizure, the drugs were replaced with flour, cables say.

Leaders of Mexico's beleaguered military issued private pleas for closer collaboration with the drug agency, confessing they had little faith in their own police forces.

Cables from Burma, the target of strict sanctions, describe both the military junta's use of drug money to enrich itself and opponents' political activities.

Cables describing the drug war do not offer significant disclosures. Rather, it is the details that add up to a clearer picture of the corrupting influence of big traffickers, the tricky game of establishing which foreign officials are controlled by drug lords, and the story of how an entrepreneurial agency operating in the shadows of the FBI has become more than a drug agency.

The DEA now has 87 offices in 63 countries and close partnerships with governments that keep the CIA at arm's length.

Due to the ubiquity of the drug scourge, today's DEA has access to foreign governments that have strained relations with the US. Many want to use the agency's drug detection and wire-tapping technologies.

Sometimes the collaboration seems to work, with intelligence helping to bring down cartels. But cables also say many informants and agents have been killed in Mexico and Afghanistan.