President Donald Trump‘s border czar clarified that U.S. Immigration and Customs Enforcement officers cannot briefly detain suspected illegal immigrants based on physical appearance alone.

“Let me be clear: Physical description can’t be the sole factor to give you reasonable suspicion,” Tom Homan told CNN on Sunday. “It’s articulable facts, with an ‘s.’ So appearance can be just one. For instance, if someone has an MS-13 tattoo on their face, that may be one factor to add to other factors to raise reasonable suspicion.”