The head of the Comprehensive Nuclear-Test-Ban Treaty Organization sees the recently expired Intermediate-Range Nuclear Forces Treaty between the United States and Russia as an "opportunity" to create a new nuclear disarmament framework.

"The situation of the INF treaty proves once again that nothing is perfect. But one thing you should remember is that everything is perfectible," Lassina Zerbo, executive secretary of the preparatory commission of the CTBTO, told Kyodo News in a recent interview.

(Lassina Zerbo)

The landmark nuclear arms control pact, signed in 1987 by then U.S. President Ronald Reagan and Soviet leader Mikhail Gorbachev, banned the nations from fielding land-based missiles with a range of 500 to 5,500 kilometers. It came to an end on Aug. 2, raising fears of a new arms race.

The United States had long contended that Russia was breaching the pact, which Russia denied. U.S. President Donald Trump announced his intention to withdraw from the pact in October last year.

Trump has called for negotiations for a new treaty involving China, although Beijing has remained reticent about such a pact.

"First thing is that we live in a world with a deficit of trust," said Zerbo, a Burkina Faso native who visited Hiroshima to attend the memorial ceremony on the 74th anniversary of the atomic bombing of the city.

"I wouldn't take the limbo in a pessimistic way. I will take it still as an opportunity to recreate better conditions for disarmament for all," he said, calling for diplomatic trust-building efforts through strengthening of global nuclear test monitoring.

With more countries than the five officially recognized nuclear powers possessing nuclear weapons, "there is the opportunity to bring all those countries" into a new multilateral agreement, said Zerbo, adding the CTBT can help bridge gaps.

A shift of focus to a multinational approach in nuclear disarmament should also help make progress toward the CTBT's entry into force, he added.

With the collapse of the INF, the international community needs to "look at the international agreement that brings the majority of people to the table," he said.

The CTBT was adopted by the U.N. General Assembly and opened for signature in 1996. Of 184 signatories, 168 have ratified it. For the treaty to come into effect, all 44 nuclear-capable states need to sign and ratify it, but some including the United States, China, India, Iran, Israel and Pakistan have yet to do so. Japan ratified it in 1997.

"One thing that both the U.S. and Russia agree on is the solidity of scientific and technological know-how that the CTBT has created," said Zerbo.

The CTBTO provides the International Monitoring System, a worldwide system that detects nuclear explosions by collecting seismic data and observing radioactive particles among other verification technologies. Zerbo says 92 percent of the system's 337 facilities including monitoring stations and laboratories around the world are in operation, and they have collected key data for detection of nuclear tests conducted by North Korea.

Referring to the U.S.-Iran standoff, Zerbo said Iran's role in completing the monitoring network should benefit the country. The CTBTO has a certified IMS facility in Tehran which used to transmit its data.

Iran signed the CTBT in 1996 but has not yet ratified it.

"The station is not transmitting data now, but we're working closely with the Iranians to resume transmission of data," Zerbo said.

While refraining from commenting on Iran's nuclear activity, Zerbo said, "Any gesture that goes toward fulfilling the spirit of the treaty, that is signed by Iran, indeed will increase trust not only in the region but internationally."

As for a U.N. treaty banning nuclear weapons not yet signed by nuclear powers, Zerbo spoke cautiously about prospects of it entering into force.

The Treaty on the Prohibition of Nuclear Weapons adopted in July 2017 by 122 U.N. members has not been ratified by the required 50 members. Japan, despite being the only country to have suffered the devastation of atomic bombings, has refused to sign the treaty along with other countries under the U.S. nuclear umbrella.

"The question has always been how we achieve a ban on nuclear weapons without the participation of the nuclear weapon countries. What we have to do is create the conditions for (those) countries to be part of this framework," he said.