AFP - Iran said on Tuesday it has no faith in world powers and called on them to create conditions which would earn Tehran's trust before the Islamic republic was willing to enter a nuclear fuel exchange deal.

Iranian foreign ministry spokesman Ramin Mehmanparast at a media conference also shrugged off threats of sanctions from some Western powers, saying this would only help Tehran gain further self-sufficiency in its atomic programme.

"We never said we will not do this (nuclear fuel deal)," Mehmanparast told reporters when asked whether Iran was still considering entering the deal brokered by the International Atomic Energy Agency (IAEA).

The deal envisages Iran sending its low-enriched uranium (LEU) abroad to be converted into fuel for a research reactor based in Tehran.

Iran has rejected the deal, demanding a simultaneous exchange of the enriched uranium inside the country.

"The question is the attitude of some Western countries in the past. They have lost trust and have never kept their promises," Mehmanparast said.

"We can't listen to them easily. If they can provide conditions that can gain our trust, we are ready to exchange the fuel."

Mehmanparast dismissed Western threats to impose a fourth set of UN sanctions on Tehran if it does not come clean on its nuclear programme.

"This is the continuation of the same incorrect approach of the past. Such threats and deadlines do not work. Sanctions are nothing new for Iran," he said.

"At every stage of sanctions, we have reached a higher level of self-sufficiency and gained further independence. If there is another round of sanctions we will be more serious" in pursuing nuclear technology.

Western powers suspect Tehran is pursuing nuclear technology to make atomic weapons. Iran denies the charge, saying its ambitions are to gain peaceful nuclear power.