Mexican authorities took custody of 74 American youths who were attending irregularly-operated boarding schools in the coastal city of Ensenada and the expatriate colony of Chapala, in western Mexico, and returned them to the United States.

The youths, who were found to be in Mexico without proper travel or residency documents, were handed over to US consular officials and then taken to Los Angeles, the Interior Department, which oversees migratory issues, said in a press statement.

The statement bore the title, "the immigration institute rescues 74 US youths with supposed behavioural problems". US consular authorities were not immediately available for comment on the whereabouts of the students.

The Interior Department said the schools which it identified as The Mission school in Ensenada, Baja California, and the Abundant Life Academy in the town of Chapala in Jalisco state were raided because they "did not comply with sanitary regulations".

"It is important to stress that none of the raids involved violence, and the human rights and personal safety of the youths were fully respected," according to the Interior Department press statement.

Immigration agents found 57 students at the Ensenada facility, and 17 in Chapala. Mexican authorities identified the schools as facilities for children "with behaviour problems".

An Abundant Life website described the Abundant Life Academy at Lake Chapala, a boarding school, as "the answer for the gifted yet immature American troubled teen that is unmotivated and rebellious toward parental authority".

Some schools in Ensenada, meanwhile, have had a history of problems.

In September, a lack of doctors and reports that some teens were being abused prompted Mexican authorities to shut down three centres for troubled youths in Baja California.