Thirteen judges on the 4th U.S. Circuit Court of Appeals will be asked to decide if the ban violates the constitution by discriminating against Muslims, as opponents say, or is necessary to protect national security, as the Trump administration says.

The hearing scheduled Friday comes four days after the U.S. Supreme Court ruled that the Trump administration can fully enforce the ban even as the separate challenges continue before the Richmond, Virginia-based 4th Circuit and the San Francisco-based 9th Circuit appeals courts.

The 4th Circuit is being asked to reverse the decision of a Maryland judge whose injunction in October barred the administration from enforcing the ban against travelers from Chad, Iran, Libya, Somalia, Syria and Yemen who have bona fide relationships with people or organizations in the U.S. The ban also applies to travelers from North Korea and to some Venezuelan government officials and their families, but the lawsuits didn't challenge those restrictions.

Trump announced his initial travel ban on citizens of certain Muslim-majority nations in late January, bringing havoc and protests to airports around the country. A federal judge in Seattle soon blocked it, and courts since then have wrestled with the restrictions as the administration has rewritten them. The latest version blocks travelers from the listed countries to varying degrees, allowing for students from some of the countries while blocking other business travelers and tourists, and allowing for admissions on a case-by-case basis.

Opponents say the latest version of the ban is another attempt by Trump to fulfill his campaign pledge to keep Muslims out of the U.S. The administration, however, says the ban is based on legitimate national security concerns.

The 4th Circuit rejected an earlier version in May, finding that it "drips with religious intolerance, animus and discrimination" toward Muslims. The judges cited Trump's campaign pledge on Muslim travelers, as well as tweets and remarks he has made since taking office.