A new U.S. ban on visitors with visas from seven Muslim-majority countries is attracting worldwide media coverage.

But another clause in President Donald Trump's January 27 executive order hasn't elicited nearly as much attention—and it will affect everyone who visits America.

Section 7 calls on the U.S. Department of Homeland Security to "the completion and implementation of a biometric entry-exit tracking system for all travelers to the United States".

This was a recommendation from the National Commission on Terrorist Attacks on the United States.

Biometrics relies on computer analysis to record a person's physical and behavioural characteristics to help ensure the authenticity of their identity.

It can entail looking at face recognition, fingerprints, palm veins, DNA, iris recognition, and even a person's odour or scent. In addition, behavioural characeristics, such as a person's gait or voice, can also be analyzed.

DHS's first report on biometrics must be submitted within 100 days of the executive order, with another report in 200 days and follow-up reports on an annual basis.

In addition, anyone seeking a nonimmigrant visa to the United States will have to undergo an in-person interview, according to Section 8 of the executive order, "subject to specific statutory exceptions".

"As far as the Biometric Entry-Exit Tracking System is concerned, this is pretty much the second piece of what is already in place today when you enter the U.S. and have your fingerprint and picture taken (at least as a foreign visitor)," states the LoyaltyLobby travel website. "Having an immigration counter upon exiting the country would basically just reconcile the information with what you gave when you came in."

According to the Canadian government website, its visa officers already use biometrics to confirm a person's identity before granting a visa or a study or work permit.

Another travel website, Skift, has condemned the Trump administration's three-month ban on vistors travelling on passports from Libya, Somalia, Sudan, Yemen, Iran, Syria, and Iraq, and a permanent ban on refugees from Syria.

In an online commentary, it calls it "a deeply hypocritical move by a profoundly challenged leader".

"Nationals of countries included on the list can't be traced to any violent acts in the U.S. over the last 40 years," the website points out. "Meanwhile four predominantly Muslim countries were left off the list (Saudia Arabia, Turkey, Egypt, the UAE) if they had business interests with the president's real estate activities, despite being tied to violence in the U.S."

Trump has also banned the entry of all non-Syrian refugees to the United States for four months.