The U.S. has introduced a new system that will allow humanitarian workers to visit North Korea multiple times on a single authorization, rather than just once, an update on the State Department website showed earlier this week.

Under U.S. travel restrictions in place since Sept. 2017 and renewed earlier this month, American passport holders are not allowed to travel to North Korea. Journalists, humanitarian workers and some others could previously apply for “special validation” passports for one round-trip visit.

“In certain qualifying cases subject to additional requirements, the Department of State may approve applicants for a multi-entry special validation, permitting