U.S. authorities handed over 14,237 unaccompanied children and teenagers of different nationalities found traveling alone on the border to Mexico last year, the National Migration Institute, or INM, said.

Of the minors handed over to authorities in Mexico, 11,520, or nearly 81 percent, were Mexican and the other 2,717 were of various unspecified nationalities.

The children were all cared for the INM’s office of children’s services.

Since 2007, Mexico has had a program in effect to protect undocumented minors who are handed over by the United States, the INM said.

Countries such as Argentina, Panama, Spain, Colombia and Senegal have expressed an interest in the welfare of these children, the INM said in a statement.