The U.S. on Friday began fully implementing the so-called “travel ban,” an initiative by President Trump to restrict travelers from select countries entering the U.S.

In a press release, the State Department announced that it would begin implementing the ban on travel from nationals of Chad, Iran, Libya, North Korea, Syria, Somalia, Venezuela and Yemen after the Supreme Court reinstated the third version of Trump’s executive order on Monday.

“National security is our top priority in visa operations. Our embassies and consulates around the world are fully implementing Presidential Proclamation 9645 to protect the American people, now that U.S. Supreme Court orders permit us to do that and based on extensive guidance provided to them by the Department,” according to a statement from the department.

The State Department stressed that travel restrictions for the eight nations are not permanent, and can be lifted if countries comply with information-sharing standards set by the U.S. government on issues such as “terrorist attacks, transnational crime, and immigration fraud.”