Germany buoys UN rules on Iran

German Chancellor Angela Merkel's comments are among the strongest from any European leader since Iran rejected a U.N. demand for it to halt uranium enrichment in exchange for an offer of economic and political incentives.

"Iran's response is not satisfactory. We won't close the door to negotiations but we the international community won't stand by and watch as Iran harms the rules of the U.N. nuclear authorities," Merkel told German lawmakers in a speech.

Merkel made clear, however, that military action against Iran was not an option.

High-level EU-Iranian talks on Tehran's nuclear programme that were expected were postponed but could be held on Friday, a senior Iranian diplomat said.

Tehran, the world's fourth largest oil exporter, says its enrichment of uranium is a legal and peaceful programme to meet civilian energy needs. The United States says it is a front for perfecting technology designed to produce nuclear arms.

Growing impatient with Tehran's refusal to cease nuclear activities that could yield enriched uranium fuel for atomic weapons, Washington has been seeking support for tough economic sanctions.

Russian Foreign Minister Sergei Lavrov said any sanctions would be governed by the United Nations charter which "states unequivocally that economic measures exclude the use of force".

"As to whether we use these (sanctions) or not still needs to be defined because any impact must be commensurate to the presence of a real threat to international security," Lavrov told reporters during a visit to South Africa.

Reiterating the Russian position, he added that Russia "unambiguously prefers the path of negotiations for the resolution of the Iranian problem."

Russia is a permanent member of the United Nations Security Council along with Britain, China, France and the United States.

Russia and China fear sanctions would merely escalate the crisis and have called for renewed talks with Tehran even while it presses on with uranium enrichment.

Germany's Merkel has been reluctant join the push for sanctions but has been gradually losing hope negotiations can succeed with a country whose president has publicly called for the destruction of Israel, German officials have told Reuters.

EU foreign policy chief Javier Solana had been due to meet Tehran's chief nuclear negotiator Ali Larijani in Europe.

Aliasghar Soltanieh, Iranian ambassador to the U.N. nuclear watchdog agency, told Reuters that the talks - which were tentatively set to be held in Vienna September 6 - were put off for unspecified procedural reasons.

"We welcome the talks between Larijani and Solana. Both sides are talking to define the time of those talks and the agenda of the talks will be announced after the time has been decided," Foreign Minister Manouchehr Mottaki told a news conference in Tehran.

German Foreign Minister Frank-Walter Steinmeier said that Berlin and its allies would refer Tehran's nuclear dossier back to the Security Council if the EU does not persuade Tehran to change its behavior.

Senior officials from the six countries that made the June incentives offer to Iran -- Germany, the United States, France, Britain, China and Russia -- are due to meet in Berlin to discuss Tehran's refusal to suspend nuclear fuel work and the possibility of imposing sanctions on Iran.