Security sources said they could not rule out some aircraft also being used for smuggling people into Mexico and the United States. Guatemala has been on a U.S. government watch list for its government's failure to combat drug and people trafficking.

Security sources said the number of airstrips across Guatemala was now believed to be more than 800 and most were used as short-term take-off and landing facilities. The likelihood of early detection made the idea of permanent strips unfeasible for the traffickers, they said.

Given the margin of drug profits involved most drug traffickers are happy to have the strips destroyed after a few uses and the locations of their operations moved to new points in the forested region.

Many of the drug-trafficking outposts are concentrated in areas contiguous to Mexico, according to security sources. Guatemala is bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast.

Baltazar Gomez, director of Guatemala's National Civilian Police, identified among key drug-trafficking areas the northern department of Peten, Huehuetenango in the west, Escuintla and Retalhuleu on the Pacific coast and the north central department of Alta Verapaz.

The strips are often built, used and then destroyed within months and usually involve the collusion of jungle communities and owners of sugar plantations or land with thick forestation suitable for camouflage.

Critical to the operation is the silence of the local inhabitants and authorities throughout the various stages of the building of the air transport facilities, their use and eventual destruction and reconstruction elsewhere in the area.

Officials said Guatemala was being used as a hub to transport cocaine and heroin made elsewhere in South America first into Mexico and then into the United States.

But security sources said Guatemala's own drug production remained significant. Guatemala in 2005 cultivated 100 hectares of opium poppy after re-emerging as a potential source of opium in 2004, and also had a production of about 1 metric ton of pure heroin, according to figures from the U.S. anti-narcotic operations.

There is also widespread marijuana cultivation for mostly domestic consumption, according to security sources.