James Jones: Iran's Nukes 'Top Global Security Threat'

MUNICH, Germany – Iran's defiance over its nuclear programme poses the greatest threat to international security, US National Security Advisor James Jones warned on Saturday.

"Hanging in the balance is a nuclear arms race in the Middle East and greater proliferation world wide. I can think of no greater concern at the moment to our collective security," he said.

"Tehran must meet its responsibilities or face stronger sanctions and perhaps even deeper isolation," he told security experts and senior officials at a conference in Munich, southern Germany.

Jones said that the door for diplomacy with Iran remains open, but he underlined that "Tehran's puzzling defiance... now compels all of us to work together as allies and partners on a second track of increased pressure."