Iran is ready to discuss "common concerns" about its nuclear programme but pledged not to negotiate what technology to use, its president says.
Iran insists its nuclear programme is solely for the generation of power
Mahmoud Ahmadinejad did not say if Iran accepted a Western proposal to restart negotiations and offer incentives if Tehran suspended uranium enrichment.
"The Iranian nation will never hold negotiations about its definite rights," he said in a speech in Qazvin.
It is his first public comment since the plan was presented to Iran.
The international community is awaiting Tehran's response to the offer submitted by European Union foreign policy chief Javier Solana to Iranian officials on Tuesday.
Iran allowed to buy spare parts for civilian aircraft made by US manufacturers
Restrictions lifted on the use of US technology in agriculture
Provision of light water nuclear reactors and enriched fuel
Support for Iranian membership of World Trade Organisation
From Western diplomatic sources
Western nations fear Iran is enriching uranium to make nuclear weapons, while Tehran says its nuclear programme is for peaceful energy purposes.
On Wednesday, diplomatic sources said the offer to Iran over its nuclear programme held out the prospect that it might be able to enrich uranium at some time in the future.
Earlier, Iran's chief nuclear negotiator, Ali Larijani, said the package of proposals contained "positive steps".
Iran has so far refused to accept any deal that relies on it giving up the right to enrich uranium - which it has said is its "inalienable" right.
The BBC's Frances Harrison in Tehran says Iran has turned the nuclear issue into one of national pride, which makes it difficult to back down without being seen to compromise the country's fierce sense of independence.
The incentives package was drawn up by the UK, France and Germany, alongside the US, Russia and China, and delivered to Tehran by the EU foreign policy chief Javier Solana on Tuesday.
It is understood to include permission for Iran to buy spare parts for civilian aircraft made by US manufacturers, and the provision of light water nuclear reactors.
The uranium used to make power in light water reactors needs to be enriched, but this can be done outside the country. The reactors are more difficult than other types to use as a source of plutonium for building nuclear weapons.
28 April: UN nuclear watchdog say Tehran has ignored calls to halt uranium enrichment
Early May: UN debates draft resolution calling for halt to uranium enrichment
Mid-May: EU countries work on proposals to try to induce Iran to curb atomic programme
31 May: US offers to join direct talks with Iran, in major policy shift
1 June: US, Russia, China and three EU states agree on package of incentives and penalties
6 June: EU foreign policy chief presents proposals in Tehran
Other incentives are said to include the lifting of restrictions on the use of US technology in agriculture and support for Iranian membership of the World Trade Organisation.
The US earlier warned Iran a rejection of the proposals could bring UN-imposed penalties.
That would depend on passing a resolution on sanctions at the UN Security Council, where unanimity between the US and Europe on one hand, and Russia and China on the other, has been difficult to achieve.