In a statement provided to Engadget, a CBP spokesperson said:

"U.S. Customs and Border Protection is using biometric facial comparison technology to facilitate the entry and exit of international travelers while meeting the Congressional mandate to implement a biometric entry-exit system. U.S. citizens are out of scope of the mandated biometric entry-exit program. However, U.S. citizens are required to establish identity and citizenship to CBP and present a valid U.S. passport for international travel.

CBP did consider including US citizens in its facial recognition checks to avoid the challenges of having separate processes for foreign nationals and US citizens, TechCrunch reports. "Upon consultation with Congress and privacy experts, however, CBP determined that the best course of action is to continue to allow U.S. citizens to voluntarily participate in the biometric entry-exit program," a CBP spokesperson said.

The ACLU, which spoke out against plans to conduct biometric scans on US citizens, is still concerned. In a statement, ACLU Senior Policy Analyst Jay Stanley said: