GENEVA - Security arrangements that have supported global peace for decades are unravelling, the head of the United Nations (UN) warned on Monday as he urged countries to work together towards a nuclear free world.

"The bilateral and regional security arrangements that underwrote global peace and stability for decades are unravelling before our eyes," UN Secretary General Antonio Guterres told the Conference on Disarmament that gathered in Geneva.

"Trust is sinking, while uncertainty, insecurity, impunity and military spending are all rising," Guterres added.

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Such factors were weakening the spirit of "mutual restraint", he said, as he called on countries to implement nuclear disarmament and non-proliferation commitments agreed at a summit in New York last September.

It focuses on negotiating deals to end the nuclear arms race and stop countries building up weapons in space, on top of pursuing general disarmament.

Artificial Intelligence (AI) was becoming weaponized at an alarming pace and there were signs of new arms races, including in outer space, Guterres warned.

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He condemned countries that "outrageously rattle the nuclear sabre as a means of coercion".