The U.S. Department of State will extend a ban on U.S. citizens traveling to North Korea for another 12 months due to ongoing safety concerns, according to a notice of extension filed in the U.S. Federal Registry on Thursday.

The original ban, which took effect from September 1, 2017, was originally imposed under then Secretary of State Rex Tillerson and came partly in response to the death of U.S. citizen Otto Warmbier, who had fallen into a coma while imprisoned in the North and died soon after being returned back to his home country.