The United States has named North Korea one of the worst human trafficking nations for the 18th consecutive year.

The State Department's annual "2020 Trafficking in Persons Report" put North Korea in the lowest Tier 3, together with China, Russia and Iran.

Releasing the report on Thursday, the department said the North Korean government did not fully meet the minimum standards for the elimination of trafficking and did not make significant efforts to do so.

The report said there was a government policy or pattern of forced labor through mass mobilizations of adults and children, prison camps and labor training centers, and its imposition of forced labor conditions on North Korea's overseas contract workers. 

It also said North Korea used proceeds from state-sponsored forced labor to fund government functions as well as other illicit activity, adding the government did not demonstrate any efforts to address human trafficking.