"Suspension is unacceptable," said Mohammad Ali Hosseini at a news conference, noting that there is no ground to do that.

"This issue belongs to the past. There is no legal and logical justification for that," he said.

After imposing sanctions against Iran for its failure to suspend the uranium enrichment, the UN Security Council has set Tehran a new deadline of Feb. 21 to freeze the sensitive atomic work.

On Saturday, Iranian Supreme Leader Ayatollah Ali Khamenei emphasized his country's need to produce nuclear fuel, saying its oil and gas reserves would dry up eventually.

"Oil and gas resources will not last forever," Khamenei was quoted by the Iranian Student's News Agency (ISNA) as saying in a speech.

"If a country does not consider this fact it will turn to a dependent country for energy in the future," the Iranian supreme leader said.

He also said that Iran would make no concessions over its nuclear rights.

"The willingness to go forward (in the nuclear field) should not be stopped and we cannot be weak," said Khamenei.

Iran, the world's fourth largest producer of crude oil with the second largest natural gas reserves, says it needs to produce nuclear fuel as a peaceful, alternative energy source.

However, the West has accused Iran of trying to produce nuclear weapons under a civilian cover, a charge denied by Tehran.

Last December, the UN Security Council passed Resolution 1737, imposing sanctions on Iran's nuclear and missile programs and calling on Tehran to suspend its enrichment activities. Iran has rejected the resolution and vowed to install 3,000 centrifuges by March 2007.