U.S. officials are warning that dangerous criminals are hiding in illegal alien caravans that are making their way to the United States, as Fox News reports.

According to the report, “gang members from El Salvador, Guatemala, and Honduras” have hidden themselves among the caravans that travel to the United States, often in the thousands, to hide themselves among illegal aliens that don’t commit other crimes besides illegal immigration. Some of the criminals in question even commit crimes in the various countries they pass through along the way.

The assertion was made by Gissell Artiga, a spokeswoman for the Joint Border Intelligence Group, an international immigration control group that includes the United States. Artiga said that “it has been possible to identify these people at the border, they camouflage themselves among the victims of human trafficking, the migrants, for they can continue committing crime in the United States and now in Mexico.” Artiga also confirmed that among the criminals in question are members of the notorious gang MS-13.

As such, JBIG and other groups have worked to identify and single out these individuals as a priority. Last year, in a migrant caravan of approximately 1,600, 25 of them were members of MS-13, who were promptly deported from Mexico.