Last week, after a private huddle of envoys from the major powers, US Ambassador John Bolton had said the six would resume their deliberations probably on Monday.
But with Russia's UN envoy Vitaly Churkin not due back here until on Thursday from Moscow where he is to attend talks there with South Korean Foreign Minister and incoming UN secretary general Ban Ki-Moon, the next round was unlikely to take place before Friday, several diplomats said on Monday.
"We are aiming at a meeting by the end of the week," a Western diplomat said.
The six envoys from the UN Security Council's five veto-wielding members -- Britain, China, France, Russia and the US -- along with Germany held a first private meeting on Thursday on a draft resolution urging nuclear and missile-related sanctions against Tehran over its refusal to halt sensitive nuclear fuel work.
The bargaining promises to be long and tough as Russia and China signalled their reluctance to accept biting sanctions against Iran, a major energy and trade partner.
Russian President Vladimir Putin told his Iranian counterpart Mahmoud Ahmadinejad on Monday that Moscow favoured continued talks over Iran's nuclear program.
In a telephone conversation, "Putin put forward the principled position of Russia in favour of continuing the process of negotiations during a discussion of the situation surrounding Iran's nuclear programme," the Kremlin press service said in a statement.
Russian Foreign Minister Sergei Lavrov last week rejected the sanctions put forward by Britain, France and Germany in consultations with Washington, arguing that they did not advance objectives agreed on by six leading world powers concerned with the case.
The Chinese stance has yet to be clarified, although Beijing -- like Moscow -- is an economic ally of Iran and traditionally reluctant to use sanctions for diplomatic leverage.
Meanwhile Ahmadinejad on Monday warned Iran would react firmly to any UN sanctions imposed on Tehran.
"We are not looking for tension but any action that aims to limit us will receive an appropriate and firm response from the Iranian people," he said during a gathering in Pishva in Tehran province.
Iranian officials have already vowed the Islamic republic would hit back against any eventual sanctions but have said the nature of the retaliation would only be revealed if and when the penalties are imposed.
On Saturday, Tehran confirmed that it had successfully enriched uranium from a new cascade at a nuclear plant, hailing the move as a step towards industrial-scale enrichment.
Enrichment, carried out in lines of centrifuges called cascades, is used to make fuel for civilian nuclear reactors. In highly refined form, however, the product can also serve as the raw material for atomic weapons.
Western countries suspect that Iran's enrichment program is designed to supply material for a nuclear weapon, while Tehran insists its fuel processing is for peaceful purposes.
Copyright AFP (Agence France-Presse), 2006
