UNITED NATIONS (AP) — The Non-Aligned Movement, representing over 100 developing countries, urged Secretary-General Ban Ki-moon and the United States, Britain and Russia on Monday to convene a long-delayed international conference to promote a nuclear-weapon-free zone in the Middle East.

Indonesia’s Foreign Minister Marty Natalegawa made the appeal on behalf of NAM members of the Nuclear Nonproliferation Treaty at the opening of the third and final preparatory conference for next year’s review of the landmark 1970 agreement aimed at stopping the spread of nuclear arms.

He reiterated NAM’s demand that Israel, the only country in the region that has not joined the NPT, “renounce possession of nuclear weapons” and join the treaty without delay. Israel is widely believed to possess nuclear weapons but has never admitted it.

The Arab proposal for a nuclear-weapon-free zone in the Middle East is designed to pressure Israel to give up its undeclared arsenal.

At the last NPT review conference in May 2010, the 189 member nations that are party to the NPT called for convening a conference in 2012 “on the establishment of a Middle East zone free of nuclear weapons and all other weapons of mass destruction.”

It was scheduled to take place in Finland in late 2012, but the United States said it would be delayed, apparently to save Israel embarrassment for refusing to attend, and no new date has been set.

Natalegawa said NAM parties to the NPT are seriously concerned that the meeting has not been held, which could have “negative repercussions” on the NPT and the 2015 review conference “and the nuclear disarmament and nonproliferation regime as a whole.”

He urged the UN, US, Britain and Russia to focus on convening the conference “at the earliest date in 2014,” and to seek “credible assurances” in advance “regarding the unconditional participation of Israel, the only country that has not declared its participation in the conference.”

Iran, Israel and Arab states did take part in an informal meeting last October in the Swiss village of Glion near Montreux on prospects for an international conference on banning nuclear weapons in the Middle East, and there have been follow-up meetings. Veteran Finnish diplomat Jaakko Laajava, who is serving as “facilitator” of the conference, has also attended.

UN disarmament chief Angela Kane told Monday’s meeting that efforts to convene a conference in Helsinki have benefited from “the constructive engagement” of Mideast states in Glion in recent months.

“As we work to build on the gains we have made, I continue to hope that the conference will be convened as soon as possible in 2014,” she said.

Copyright 2014 The Associated Press.