By Nick Miles BBC correspondent in Mexico City

Police in Mexico say they have caught a group of 92 illegal Central American migrants hiding in the back of a lorry which had come from neighbouring Guatemala.

More than 2,000 people died last year trying to reach the US

Highway patrol officers in the southern state of Chiapas found the migrants when they were searching the refrigerated trailer of the lorry.

On Wednesday police in the United States found the bodies of 18 illegal migrants from Mexico and other Central American countries who had died of dehydration, hyperthermia and suffocation in another trailer.

Until recently crossing Mexico's southern border was the easy part of the migrants' journey to the United States. No longer.

As part of a commitment to improve border security, patrols have tripled in the last two years and, as this latest find shows, it is paying off.

The lorry's cargo should have been floor tiles but when police checked they made their largest single find of illegal migrants in several years.

Most of the 92 people inside were young men from Honduras, El Salvador and Guatemala.

Many of them were suffering from hypothermia.

Perilous journey

Thousands of illegal migrants from Latin America cross into the US from Mexico every year.

It is a perilous journey for them. Getting into Mexico they run the risk of drowning in the border river or being assaulted by armed groups of robbers.

If and when they reach the US frontier, they then have to confront long walks through the searing heat of the Sonora desert to reach their goal.

More than 2,000 people died trying to cross the border last year alone, most from dehydration.

Mexico is planning a publicity campaign aimed at reducing deaths among people trying to cross but previous campaigns have had little effect.

More than two million people are thought to attempt the journey every year, spurred on by growing levels of poverty in many parts of the region.