Despite actively pursuing diplomacy on its nuclear program, North Korea continues to quash basic freedoms, maintaining political prison camps and strict surveillance over its citizens, a United Nations human rights investigator said Friday.

"With the positive developments in the past year 2018, it is all the more regrettable that the serious human rights situation on the ground in the Democratic People's Republic of Korea remains unchanged," Tomas Ojea Quintana, U.N. special rapporteur for human rights in the DPRK, said in his latest report.

North Korea has frozen its nuclear and missile testing since 2017 and held several summits with the United States and South Korea in the past year, emerging from decades of isolation.