UNITED NATIONS, Feb 23: Five permanent members of the United Nations Security Council -- China, Russia, France, Britain and the United States -- have begun consultations over Iranian nuclear programme issue following disclosure by UN's watchdog atomic agency that Tehran had failed to comply with the council's demand to stop its nuclear enrichment programme, diplomats here said on Friday.

Senior envoys of the five permanent members of the 15 member security Council will meet in London on Monday to start work on a resolution and devise a way to bridge the impasse.

As expected Britain has joined the United States in calling for harsher sanctions against Iran but the diplomats here also believe that China and Russia will caution less dramatic moves and will seek more diplomatic efforts.

Iranian President Mahmoud Ahmadinejad vowed on Friday that Iran would defend its nuclear programme, describing his country as a potential role model for others trying to develop advanced technology.

Meanwhile, Russian Ambassador Vitaly Churkin on Friday called for a diplomatic solution to the issue instead of imposing additional sanctions against Iran.

Responding to questions at UN Headquarters in New York, he said he had "no substantive comment" on the IAEA report but reiterated Moscow's desire for a diplomatic solution.