Mexican migrants recently caught trying to cross into the US say they had paid traffickers as much as $3,000 for safe passage.

It is the third time that a large group of migrants has been intercepted by Mexican authorities this year.

Last May more than 500 migrants from Central America, Nepal, India, Japan and China were found in dire health conditions inside a trailer tractor on their way to the US.

The National Commission for Human Rights says 20,000 migrants are abducted every year and hundreds are believed to have died in the process.

US immigration experts assert the only way to stop this crisis is if the policies in the migrants' home countries could be recast to prevent them from leaving in search of a better life elsewhere.

Al Jazeera's Mariana Sanchez reports from Mexico City.