TEHRAN, June 25 (RIA Novosti) - The resumption of a moratorium on uranium enrichment will be a step back, Iranian Foreign Ministry spokesman Hamid Reza Asefi said Sunday.

Iran's nuclear program has been a source of major controversy since the beginning of the year, as many countries suspect the Islamic Republic of pursuing a covert weapons program under the pretext of civilian research, despite its claims to the contrary.

The United States, France, Germany, Britain, Russia and China have agreed a package of incentives for Iran in return for its consent to stop its nuclear enrichment program. EU foreign policy chief Javier Solana presented the offer to Tehran during his visit to Iran June 6.

Asefi said negotiations without any preconditions were the only right way to reach agreement on the Iran nuclear issue. He added that the package of proposals from the six world powers was a step in the right direction.

Asefi said Tehran would study the proposals carefully.

"The reason that there can't be a speedy response is that we have to hold serious discussions on the contents," Asefi said.