A letter sent to Alice ISD parents Wednesday said a student may be detained and possibly deported if they cannot prove they are in the country legally.

A South Texas school district is warning parents that U.S. Border Patrol agents may be checking the immigration status of students as they participate in extracurricular activities. On Wednesday, the Alice Independent School District sent out a letter alerting parents that agents may be boarding school buses to question students about their citizenship status.

The accord will expand the Trump administration’s footprint by deputizing National Guard members as immigration agents.

That policy change was made official Sunday after Abbott and Pete Flores, the acting commissioner of U.S. Customs and Border Protection, signed a memorandum of understanding that grants Guard troops the expanded authority.

A line of Mexican National Guard and Army trucks rumbled along the border separating Ciudad Juárez and El Paso, Texas, on Wednesday, among the first of 10,000 troops Mexico has sent to its northern frontier following tariff threats by President Donald Trump.