UNITED NATIONS (AP) — A major U.N. conference to review the Nuclear Nonproliferation Treaty, considered the cornerstone of global efforts to prevent the spread of nuclear weapons, is “likely to be postponed” because of the coronavirus pandemic, a U.N. official said Tuesday.

U.N. deputy spokesman Farhan Haq said that was the assessment from conference president-designate, Ambassador Gustavo Zlauvinen of Argentina, and key organizers of the conference that has been scheduled for April 27-May 22 at U.N. headquarters in New York.

The organizers are continuing consultations with all governments “to allow the review conference to undertake its important work when conditions permit,” Haq said.

“A decision is expected to be taken in the coming week, following further consultations with regional groups,” he said.

Zlauvenin initially wrote to treaty political groups on March 13 proposing a postponement “after a short, procedural meeting on April 27, for New York-based delegates only and conditions permitting,” Haq said. But “in light of the rapidly evolving situation surrounding the spread of COVID-19,” all options about the April 27 meeting are being considered.

The Nuclear Nonproliferation Treaty, which reached its 50th anniversary March 5, is credited with preventing the spread of nuclear weapons to dozens of nations.

It has succeeded in doing this via a grand global bargain: Nations without nuclear weapons committed not to acquire them; those with them committed to move toward their elimination; and all endorsed everyone’s right to develop peaceful nuclear energy.

Treaty members gather every five years to review how it is working That includes every nation except India, Pakistan and North Korea, which possess nuclear weapons, and Israel, which is believed to be a nuclear power but has never acknowledged it.

Members try to agree on new approaches to problems, not by updating the treaty which is difficult, but by trying to adopt a consensus final document calling for steps outside the treaty to advance its goals. That has also proven difficult at recent review conferences,

U.N. disarmament chief Izumi Nakamitsu warned earlier this month that the specter of an unbridled nuclear arms race is threatening the world for the first time since the 1970s, the height of the Cold War between the United States and the former Soviet Union.

She didn't name any countries but she was clearly referring to the United States and Russia, and possibly China, when she told the U.N. Security Council that "relationships between states — especially nuclear-weapon states — are fractured."

“So-called great power competition is the order of the day.” Nakamitsu said.

Russia-U.S. relations have been at post-Cold War lows since Moscow's 2014 annexation of Ukraine's Crimea.

Russia and the U.S. clashed at the Security Council meeting where Nakamitsu spoke but they joined in supporting a statement saying the treaty "remains the cornerstone of the nuclear nonproliferation regime and the foundation for the pursuit of nuclear disarmament and the peaceful uses of nuclear energy."

The council resolved to advance the treaty's goals and underlined its essential role “in the preservation of international peace, security and stability as well as the ultimate objective of a world without nuclear weapons.”