By Dan Williams

JERUSALEM (Reuters) - Iran and Israel have been cooperating under the auspices of an international body set up to monitor a ban on nuclear bomb tests, its director said on Monday.

Negotiated in the 1990s, the Comprehensive Nuclear Test Ban Treaty enjoys wide global support but must be ratified by eight more nuclear technology states -- among them Israel and Iran, as well as Egypt and the United States -- to come into force.

In the interim, Middle East signatories have regularly held technical meetings, including in Jordan in November and December to practice detecting illicit testing.

"Iran took part in the drill. Egypt was part of this drill. I think all the Arab countries were represented in Jordan for this exercise," Lassina Zerbo, executive secretary of the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO), said during a visit to Israel.

"During the exercise, when we had our round-table discussions or dinner or lunches, you had Iranian experts and Israeli experts sitting at the same table," he told Reuters. "It's not unusual that we see that in the technological field we have people who don't necessarily get together politically but who find things to agree on in the scientific framework."

The CTBTO has established a system to detect any nuclear blasts, with more than 337 monitoring facilities in the world.

Among these are two seismic stations in Israel and another in Iran which, Zerbo said, has been inactive since 2006 when the international network was upgraded and sanctions on Tehran over its nuclear program made taking equipment there difficult.

An April 2 framework deal between Iran and world powers clears the way for a settlement to allay Western fears that Iran could build a nuclear weapon, with economic sanctions on Tehran being lifted in return.

Zerbo voiced hope of getting the Iranian site back on line, effectively putting Iran on the same detection grid as Israel, which accuses Tehran of harboring designs on nuclear weaponry.

Story continues

Israel -- which is believed to be the only nuclear-armed state in the Middle East, but neither confirms nor denies this -- says it believes Iran is committed to its destruction.

Iran insists its nuclear projects are purely peaceful, a position Zerbo argued would be shored up by ratifying the Test Ban treaty. But, he said, "their approach is that diplomacy is always one step at a time."

By not signing the voluntary nuclear Non-Proliferation Treaty, to which Iran belongs, Israel has kept its main nuclear facilities away from foreign inspection.

(Editing by Jeffrey Heller and Janet Lawrence)