“Those who think that with outmoded instruments like psychological warfare and economic sanctions they can stop Iran’s march towards progress are making a grave mistake,” Ahmadinejad told a major military parade in Tehran.

Diplomats from the five permanent members of the UN Security Council along with Germany met in Washington on to discuss further sanctions against Iran, in an encounter hosted by US under secretary of state Nicholas Burns.

According to US media, the state department described the meeting as “serious and constructive,” without giving further details.

However the media said that there were still significant differences between Europe and the United States on one side and on the other Russia and China, which were against imposing further sanctions for the moment.

The UN Security Council has already issued two resolutions imposing sanctions to punish Iran’s refusal to suspend sensitive uranium enrichment operations, which the West fears could be used to make nuclear weapons.

However Tehran insists that its nuclear programme is aimed solely at producing energy for a growing population.