In nearly all cases, the children had already been arrested at least once, and some more than five times, in attempts to cross the US border.
The children make the gruelling journey of hundreds of miles (kilometers) through Mexico to escape dire economic conditions and violence in their home countries, and to join relatives in the United States.
"From January 1 to April 30, 2014, the Mexican consular network offered assistance to 6,233 unaccompanied Mexican minors... In the process of their repatriation to Mexico," a statement from the foreign ministry said yesterday.
Once intercepted by US border agents, "the unaccompanied minors are transported to border patrol stations and are placed in holding rooms" before being turned over to Mexican immigration agents.
In recent months, a surge of unaccompanied children has flooded the southwestern US border, most from El Salvador, Honduras and Guatemala.
More than 47,000 children crossed the border illegally without an adult between October and May, nearly doubling the figure from the six months prior, in what President Barack Obama and leading lawmakers have termed a humanitarian crisis.