The flow of Central American migrants throu2gh Mexican territory fell 70 percent from 2005 to 2010, with crossings dropping from 433,000 to 140,000, the National Migration Institute, or INM, said.

This trend started in 2006 and accelerated due to the "slowdown in the U.S. economy since 2008," INM director Salvador Beltran del Rio said during a presentation on the challenges posed by the international movement of people.

The dangers for Central Americans have increased in the past few years as criminal organizations became involved in people trafficking, extortion rackets and kidnappings of migrants, Beltran said.

A total of 46,914 foreigners, the majority of them from Central America, were processed at immigration stations between January and August, a drop of 9 percent compared to the same period in 2010, Beltran said.

The number of female migrants fell in the past three years, while the number of unaccompanied minors rose, the INM director said.

Most Central American migrants do not work in Mexico and spend less than a month in the country, Beltran said.

The most recent Southern Border Migration Survey found that six of every 10 migrants employed a guide to cross into the United States and 43 percent used guides on the journey across Mexico, the INM director said.