The Vatican representative to the world’s nuclear body on Tuesday said nuclear weapons “provide a false sense of security” and added he is “concerned” about the situation on the Korean peninsula.

Monsignor Janusz S. Urbańczyk, the Vatican representative to the International Atomic Energy Agency (IAEA), was speaking at the first meeting preparing for the 2020 Review Conference of the Treaty on the Nonproliferation of Nuclear Weapons (NPT) taking place in Vienna.

The treaty, considered the main international nonproliferation tool, went into effect in 1970, and a review process is conducted every 5 years.

Urbańczyk said the Vatican, which signed the NPT in 1971, was taking part in the preparatory meeting “to lend its moral authority” to the process.

“The Holy See cannot but lament the fact that the potential devastation caused by the use of nuclear weapons so clearly identified over 40 years ago has not been relegated to history,” the diplomat said. “In other words, the efforts of the international community to utilize the NPT to make the world safer have not been sufficient.”

He said the preparatory meetings and the 2020 review conference itself should “make concrete and consensus-based progress” to stop the spread of nuclear weapons, and work towards “the ultimate goal of abolishing all nuclear weapons.

“Pope Francis, following in the footsteps of his venerable predecessors, has repeatedly called on the international community, not only to seek the end of war, conflict and strife, but to embrace forcefully and advance peace,”  Urbańczyk said, “the value of peace must be recognized as an ‘active virtue,’ calling for the engagement and cooperation of each individual and society as a whole.”

In March, the United Nations General Assembly hosted a conference in New York to work towards a treaty banning nuclear weapons, which was boycotted by all the nuclear powers.

Francis wrote a personal letter to that conference, offering his support, and calling for a “collective and concerted multilateral effort to eliminate nuclear weapons,” adding that international peace and stability “cannot be based on a false sense of security, on the threat of mutual destruction or total annihilation, or on simply maintaining a balance of power.”

Urbańczyk on Tuesday acknowledged nations have “a right and an obligation” to protect their own security, but said this is “strongly linked” to the promotion of collective security, the common good, and peace.

“In this perspective, a positive conception of peace is required,” he said, adding that peace must be built on justice, on integral human development, on respect for fundamental human rights, on the protection of creation, and on dialogue and solidarity.

Urbańczyk urged certain concrete steps be taken to work towards nuclear disarmament: Having those countries with nuclear weapons renew arms control and disarmament processes, as called for in the NPT; bringing the Comprehensive Nuclear-Test-Ban Treaty (CTBT) into force, which would end all tests of atomic weapons; and doing more to stop nuclear proliferation, which Urbańczyk said was “a key to progress on nuclear disarmament.”

The situation surrounding North Korea was a hot topic during the preparatory meeting, and the Director General of the IAEA, Yukiya Amano, said on Tuesday the continuing development of the country’s nuclear weapons capability was “extremely worrying.”

North Korea left the NPT in 2003, and since then has conducted five nuclear tests, two of those in 2016.

Amano said “all the indications suggest that North Korea is making progress with its nuclear program.”

Urbańczyk said the Vatican is “concerned” about the situation on the Korean peninsula, and “supports the continued efforts by the international community to revive negotiations over denuclearization and peace.”

Pope Francis spoke about the nuclear crisis in Korea on Saturday, during his inflight press conference after his 27-hour trip to Egypt.

“I’ve called on [world leaders], and I will call on them, to work towards resolving the problems through the path of diplomacy,” Francis said.

Francis put his response in the context of his repeated references over the past two years to a “third world war” being fought in piecemeal fashion, in various global conflict zones, saying those pieces “have arrived and they’re concentrated” on North Korea.

Referring to the possibility of a nuclear war, the pontiff said, “It would be terrible, and I don’t believe humanity right now could take it.”