Iranian foreign ministry spokesman Hassan Ghashghavi said Iran would not listen to any deadlines and added that it was committed to following international laws when it comes to its nuclear programme.
"Our commitments under the international regulations are based on legalities. Remarks that bear threats, deadlines and timetables do not have any impact on us," Ghashghavi said at his weekly press conference, responding to Clinton's comments.
Clinton warned Iran on Sunday that world powers were running out of patience.
"The international community will not wait indefinitely for evidence that Iran is prepared to live up to its international obligations," she said after talks in London with British Foreign Secretary David Miliband.
She said the six-party talks on Iran's nuclear programme in Geneva on October 1 were a "constructive beginning" but she said they "must be followed by action."
"Words are not enough," Clinton added.
Western powers suspect Iran's nuclear programme is aimed at making atomic weapons, a charge strongly denied by Tehran.
Global powers were outraged after Iran, just days ahead of the Geneva talks, revealed to the International Atomic Energy Agency (IAEA) that it was building a second uranium enrichment plant near the holy city of Qom.
The next stage in the talks comes on October 19, when officials from Iran, the United States, Russia, France and the IAEA are to meet in Vienna to work out the deals under which Tehran has said it is ready to buy 20 percent pure uranium from abroad.
Ghashghavi said that in the upcoming talks "price, delivery and the mechanism" of imports of the fuel for Iran's reactor would be discussed.
"We are now willing to receive it… and hopefully the agreement is reached to receive the 20 percent enriched fuel," he said.
Iran has agreed to offer its low-enriched uranium for third party enrichment to a 20 percent purity level as required for its Tehran reactor.
Ghashghavi, however, reiterated that Iran would pursue enrichment activities if no deal is concluded.
"This doesn't mean that our hands are tied and we only depend on (fuel) imports… we are serious in covering our needs. If one day (the fuel is not given) we will definitely cover our needs but under legal and clear frameworks," he said.
