SEOUL, South Korea (AP) — The United Nations’ independent investigator on human rights in North Korea has called for the international community to provide 60 million doses of COVID-19 vaccines to the isolated authoritarian nation, which has recently showed signs of easing one of the world's most restrictive pandemic border closures.

Tomas Ojea Quintana said Wednesday the doses would be enough to inoculate North Korea’s population of more than 25 million people at least twice. He said the shots would possibly encourage Pyongyang’s leadership to open up more after the country’s self-imposed lockdown of the past two years created challenges for outside monitors, aid groups and diplomats.

The move could be “the key to opening (North) Korea's border and resuming its interaction with the international community and bringing it out of isolation,” Quintana said at a news conference on Wednesday in Seoul.

It’s unclear whether Quintana’s plan is feasible. The North has so far shunned millions of shots offered by the U.N.-backed COVAX distribution program, possibly because they come with international monitoring requirements. Quintana suggested promising North Korea 60 million doses up front because the country might be unwilling to receive limited volumes in phases.

North Korea in recent weeks has partially reopened railroad freight traffic with its ally China, in a move that appears to align with leader Kim Jong Un’s call for a more “scientific” virus response.

The reopening shows North Korea is exploring more sustainable ways to deal with a virus threat that may last for years, and it could also provide a glimpse into the North’s vaccine strategy following a yearlong delay in its mass immunization program.

Experts say the North may seek China and Russia's help to provide regular testing and vaccinations for workers and troops in border areas, where access from other regions is tightly restricted.

North Korea still claims to have a perfect record in keeping COVID-19 out of its territory — a claim that's widely doubted. But the closure of its border to nearly all trade and visitors for two years further shocked an economy that was already damaged by decades of mismanagement and crippling U.S.-led sanctions over Kim’s nuclear weapons and missile programs.

Quintana was one of the U.N. investigators who jointly issued a letter to North Korea’s government in August last year asking it to clarify whether it has ordered troops to shoot on sight any trespassers who cross its northern border in violation of the country’s pandemic closure. The North has not publicly commented on the matter.

In its latest report to the World Health Organization, North Korea said it has so far tested more than 54,180 people for the coronavirus as of Feb. 3, but that all tests were negative.