The United States said Friday that it hosted a working-level experts’ meeting with counterparts from China, France, Russia, and the United Kingdom in “an ongoing exchange” amid Russia’s war in Ukraine.

According to the State Department, experts from the foreign and defense ministries of the five nuclear-armed states met on June 13 and 14 in Cairo in the context of the Nuclear Non-Proliferation Treaty (NPT).

They discussed “strategic risk reduction, as well as nuclear doctrines and policy,” it said. The U.S. delegation included experts from the State and Defense Departments and the National Nuclear Security Administration.

“The U.S. delegation welcomed the professional approach of the delegations and the inclusion of defense officials in the thematic discussions,” the department said in a statement.

National security spokesman John Kirby described the nuclear weapons summit as “a routine, continuing dialogue” that allowed the experts to discuss “nuclear safety protocols and procedures.”

“We just happened to be the chair of these nuclear-armed nations, and it’s done at a working level,” Kirby told reporters in Washington on Friday.

Under the NPT’s provisions, the five nuclear powers agreed to negotiate toward eliminating their arsenals someday, and nations without nuclear weapons promised not to acquire them in exchange for a guarantee to be able to develop nuclear energy for peaceful purposes.

The meeting came as Russian President Vladimir Putin and Belarusian President Alexander Lukashenko confirmed on June 16 the deployment of tactical nuclear weapons in Belarus.

Some of the warheads are expected to be three times more powerful than the atomic bombs the United States dropped on Hiroshima and Nagasaki during World War II in 1945.

Speaking at an economic forum in St. Petersburg on June 16, Putin said that Russia had only delivered the first batch of nuclear warheads to the territory of Belarus, with the remaining deliveries expected to be completed “by the end of the summer or by the end of the year.”

Putin first described plans to deploy the nuclear warheads in Belarus in March, pointing to the U.S. deployment of similar weapons at NATO bases in a number of European countries over many decades.

The move marks Moscow’s first deployment of such tactical nuclear warheads—shorter-range, less powerful nuclear weapons that could be used on the battlefield—outside Russia since the fall of the Soviet Union in the 1990s.

U.S.-based China expert Tang Jingyuan told The Epoch Times on June 17 that the most fundamental reason for Putin’s deployment of tactical nuclear weapons in Belarus is that Russia is becoming increasingly passive on the Ukrainian battlefield.

With Ukraine’s counterattack, Russia may lose the land it has occupied and even its homeland may be hit. Therefore, Putin needs to make such a move as a way of military blackmail, to force NATO to limit military aid to Ukraine.

“This is also the first time since the end of the Cold War that a nuclear power has deployed nuclear weapons to other countries, which has seriously undermined the Non-Proliferation Treaty and may force some of the weaker countries to take an extra layer of concern when it comes to military assistance to Ukraine,” Tang said.

“But on the other hand, this move also exposed Putin’s weakness, indicating that his increasingly difficult situation on the battlefield has seriously affected the security of his power position. The expansion of nuclear weapons deployment is basically his last card, strictly speaking, he does not really want to use nuclear weapons to win the war but to use nuclear weapons to keep his position,” he continued.

Lorenz Duchamps, Jessica Mao, Olivia Li and the Associated Press contributed to this report.