"They say we want to give Iranians incentives but they think they are dealing with a four-year-old, telling him they will give him candies or walnuts and take gold from him in return," he told a crowd in the central city of Arak.
"Don't force governments and nations who are signatories to the atomic Non-Proliferation Treaty to pull out of it," he added in remarks broadcast live on state television.
Britain, France and Germany, the EU's three biggest powers, plan to offer Iran a light-water nuclear reactor as part of a package of incentives if Tehran agrees to freeze its uranium enrichment program.
Iran would then get trade benefits - Europeans have already promised to help Tehran get into the World Trade Organisation and would ratify the Additional Protocol to the nuclear Non-Proliferation Treaty (NPT) that allows for wider IAEA inspections.
But Iran would have to give up even small-scale research work in enriching uranium that it started in February at its facility in Natanz.
Agreement not expected
EU diplomats said yesterday they would be very surprised if Iran accepted but would take a rejection as confirmation that its nuclear program did not solely aim at generation for peaceful ends.
The United States and EU accuse Iran of pursuing nuclear weapons under cover of a civilian atomic energy program, a charge Tehran denies.
A European Union diplomat said political directors from the "EU3" and the office of EU foreign policy chief Javier Solana would discuss the proposal with US, Russian and Chinese counterparts in London on Friday.
"The EU3 and Solana are planning an offer of a European light-water reactor to Iran in return for a suspension of its enrichment program," the diplomat, familiar with the negotiations on Iran, told Reuters on condition of anonymity.
Nuclear experts say light-water reactors are more difficult to use for weapons purposes than heavy-water plants.
Enrichment is a process that makes fuel for nuclear power reactors but can also produce the core of a nuclear weapon.
The EU trio first proposed offering Iran light-water technology in 2005, after two years of negotiations. At the time, the Iranians said the offer lacked specific incentives.
EU diplomats said the new offer would be more specific, partly because they were confident of full US support.
Offering Iran a light-water reactor needs US backing, as European companies involved in this technology would not want to endanger their business with the United States.
Washington is apparently pleased that the EU has "for the first time committed itself to specific United Nations Security Council sanctions on Iran if Iran fails to comply."
The European Union had pledged on Monday in Brussels to make a "bold" offer to persuade Iran to curb its atomic ambitions.
But they made clear they saw little prospect that Iran would accept, and were aiming above all to demonstrate to sceptics such as Russia and China that the West was not trying to deprive Iran of civilian nuclear energy.