Mexico has said they will use satellite imagery to monitor key railway lines running toward the US border to ensure the safety of the tracks and to help stem the flow of illegal immigrants heading north for the United States.

A top interior ministry official said that a dozen satellite-monitored vehicles are to be deployed ahead of cargo trains near Mexico's southern border with Guatemala - the trains that Central American migrants often jump on as they journey north.

The vehicles will monitor the tracks, relaying real-time data on damage as well as on migrants seeking to climb on the trains.

The new technology aims to "prevent migrants from putting at risk the safety of the trains which are for cargo, not passengers," Humberto Mayans, the interior ministry's southern border coordinator, told reporters.

The government said that, in order to ferry cargo faster and deter would-be migrants, more money would be spent on maintaining tracks that have been neglected for years in six southern states. The aim is to avoid derailments and help to speed up the notoriously slow trains.

Following a surge of migrants earlier this year, the number of Central American migrants crossing illegally into the United States has fallen over the past couple months.

The fall is attributed to a combination of factors, including tighter border policing and raids on the famously dangerous "La Bestia," or the beast, cargo trains.

Horror tales told by deportees who had to contend with drug gangs on the way north, a US funded advertising blitz on the dangers of the journey, as well as the high-profile arrests of several human smugglers, or coyotes, have also served as deterrents.

In July, President Enrique Pena Nieto said he would take steps to make Mexico's porous southern border with Guatemala more secure, including improved border crossing facilities and better regional cooperation.