Mexican President Felipe Calderon says violence along his country’s border with the US is fuelled in part by the US opting to deport rather than prosecute criminals.
It was cheaper to send them back rather than try them, Mr Calderon said.
Such people, he said, then joined forces with criminal gangs in Mexico.
Nearly 400,000 illegal immigrants were deported in the past fiscal year, half of whom had been convicted of a crime, US officials said on Tuesday.
President Calderon’s remarks came during a speech at an immigration conference in Mexico City.