North Korea releases rare glimpse of Kim Jong Un touring secret nuclear weapons facility

North Korea provided a rare glimpse Friday of a secretive uranium-enrichment facility where it produces material for its nuclear weapons program when it released several images of its leader Kim Jong Un touring the site.

The photos, published by North Korea's official Korean Central News Agency , show Kim walking past rows of centrifuges and being briefed by military officials and scientists at the Nuclear Weapons Institute.

Kim expressed "great satisfaction" and "felt strong" when he inspected the facility and its accelerating production of weapons-grade nuclear materials, according to an accompanying statement released by KCNA. North Korea's leader also stressed the need for Pyongyang to "exponentially increase" its nuclear weapons stockpile.

The location of the institute was not disclosed. Nor was it clear when the visit took place, or why the photos were made public Friday. However, their release comes the same week as the first U.S. presidential debate between Vice President Kamala Harris and former President Donald Trump. Some experts have suggested the timing could be aimed at raising North Korea's nuclear profile ahead of the U.S. election and any future nuclear negotiations.

Hong Min, a senior analyst at the Korea Institute for National Unification, which is affiliated with South Korea's government, told the AFP news agency that the photographs could be an election "message" − intended to signal to the next U.S. administration that it will be "impossible to denuclearize North Korea."

Enriched uranium is an integral ingredient, along with plutonium, for manufacturing nuclear warheads. It is enriched by placing it in centrifuges − machines that spin containers at very high speeds to separate solids from liquids.

North Korea has never publicly disclosed how many nuclear weapons it possesses. A recent estimate from the Stockholm International Peace Research Institute concluded that the country has about 50 "stored" nuclear warheads, meaning they are not actively deployed on its various land-based weapons systems.

Of the more than 12,000 global inventory of nuclear warheads, more than 10,500 belong to the U.S. and Russia. according to the institute. The U.S. and Russia each have about 1,700 "deployed" nuclear warheads, meaning they are ready to be used with land-and-sea missile systems, as well as aircraft.

North Korea has conducted six nuclear tests, all underground in deep hidden tunnels under mountains. Its last nuclear test in was 2017. Cheong Seong-chang, an expert at the Sejong Institute, a think tank specializing in diplomacy and security, told South Korea's Yonhap news agency Pyongyang may be planning its seventh.

This article originally appeared on USA TODAY: North Korea releases rare glimpse of Kim Jong Un touring secret nuclear weapons facility