The U.S. administration has extended a travel ban on North Korea for another year.

The State Department on Tuesday released a notice that the ban will remain in place until August 31, 2021, unless revoked by Secretary State of Mike Pompeo. 

The department said that it determined there continues to be "serious risk" of arrest and long-term detention for U.S. nationals traveling to North Korea. 

Under the ban, all U.S. passports will remain invalid for travel to, in, or through North Korea unless specially validated for such travel. 

The ban was imposed in September 2017 following the death of American student Otto Warmbier, who died days after he returned home following his release from North Korea. The ban was renewed in 2018 and 2019.