Speaking after meeting Mohamed ElBaradei, the head of the International Atomic Emergy Agency, Iran's top nuclear negotiator repeated that the government would not bow to demands that it freeze its nuclear work.
"Every action must be reasonable and logical," said Ali Larijani.
"We are cooperating in a constructive manner with the agency, and Mr ElBaradei is here and the inspectors and cameras are here, so such a proposal is not very important to solve the problem."
ElBaradei's 24-hour visit to Tehran comes two days after Iran announced its scientists had successfully enriched uranium to make nuclear fuel, drawing strong rebukes from major world powers, including Russia and China.
Enriched uranium is used for fuel in power-generating reactors and - in a highly enriched form - for warheads in nuclear weapons. But Western diplomats and experts familiar with Iran's program say Iran still is far from producing any weapons-grade uranium.
The Islamic republic insists its programme is a peaceful effort to improve its power generating capacity.
ElBaradei said he could not yet confirm if Iran had enriched uranium to the 3.5% level as it has claimed.
"I cannot confirm that. Our inspectors have taken samples. They will report to the (IAEA) board," he said after his meetings on Thursday.
"I cannot confirm that (Iran's enrichment claim). Our inspectors have taken samples. They will report to the (IAEA) board"
The 3.5% level produced by Iran - and suitable for use in power generation - is far below the 90% required to make a bomb.
The UN Security Council has set April 28 as a deadline for Tehran to halt enrichment.
ElBaradei also said that talks on the "difficult and important" issue would continue over the next few weeks.
"I can tell you on the issue of cooperation to resolve outstanding issues, Mr Larijani renewed his commitment that the Islamic republic of Iran will accelerate its efforts to work with us in the next couple of weeks to provide clarity to the issue that we need to clarify," he said.
"On the other issue of confidence-building measures, including suspension of enrichment, we had a good discussion."
Iran’s president meanwhile has been reiterated that Iran was not prepared to give up its uranium encrichment programme - a project he says is a national right.
"We won't hold talks with anyone about the right of the Iranian nation (to enrich uranium) and no one has the right to retreat, even one iota," Mahmoud Ahmadinejad was quoted as saying late Wednesday by the official Islamic Republic News Agency.
"Our answer to those who are angry about Iran achieving the full nuclear fuel cycle is just one phrase. We say: 'Be angry at us and die of this anger.'"