As the US opposes the use of hard-and-fast deadline for Tehran to make any decision about nuclear fuel supply, Iran says it will not accept any deadline over its nuclear energy program.

US Secretary of State Hillary Rodham Clinton on Monday rejected any hard-and-fast deadline for Iran to respond.

"We've avoided using the term 'deadline' ourselves," she said and added that the administration of President Barack Obama remains open to negotiating with Iran over its nuclear program, despite intransigence from Tehran.

On Tuesday, the Iranian Foreign Ministry Spokesman Ramin Mehman-Parast reacted to remarks by the US secretary of states and said, "We also agree with Clinton's view."

"We have believed that setting any deadline by either parties (involved in nuclear talks) would be meaningless and valueless," Mehman-Parast said at his weekly news briefing.

"If parties involved in nuclear negotiations reach a consensus about cooperation with Iran (on production of nuclear fuel for the research reactor in Tehran), we will welcome (their decision). Otherwise, Iran will continue its nuclear activities," said the spokesman.

He called on the West to adopt a realistic approach to Iran's nuclear energy program and said that Iran has continuously abided by the International Atomic Energy Agency's rules and regulations.

He shrugged off US threats of sanctions and said that Iran would not be affected by sanctions.

Mehman-Parast said that imposing further sanctions on Tehran will not stop it from moving towards independence.

On Monday, Clinton said the United States has already begun discussions with its partners about imposing sanctions on Iran.

"We have already begun discussions with our partners and with like-minded nations about pressure and sanctions," she added.

She stated that the White House will continue its dual track approach of seeking to halt Iran's uranium enrichment program through negotiations while also considering sanctions.

The West is pressuring Tehran to accept a UN-backed draft deal, which would require Iran to send most of its domestically-produced low enriched uranium (LEU) abroad to be further refined for the Tehran reactor that produces medical isotopes.

The research reactor in the capital, which produces radio medicine for cancer patients, is soon expected to run out of fuel. Iran has demanded the International Atomic Energy Agency (IAEA) to arrange that fuel be provided to the country.

Iran, however, has not accepted the proposal which was first floated by the administration of US President Barack Obama. The Islamic Republic calls for "concrete guarantees" for the return of its fuel, as some Western countries have previously failed to adhere to their nuclear commitments to Tehran.