Western diplomats complained Iran had shown scant interest in following through on a plan they saw as crucial to demonstrating Tehran's nuclear ambitions are peaceful.

Iran's official IRNA news agency said on Friday that Tehran had not yet given its final response and was ready for more talks. The report suggested Iran would remain evasive.

"Even if a next round of talks was held, Iran would announce its opinion and not an answer," IRNA quoted one source as saying.

French Foreign Ministry spokesman Bernard Valero said Iran appeared to have given only a verbal indication of its position and proposed changes, which he did not specify.

In addition to the demand for fresh nuclear fuel up front, Iranian media reported that Tehran wants the low-enriched uranium to be shipped out in small, staggered portions -- not all in one go as the draft text stipulates.

This would undo key aspects of the deal for big powers, who want to minimize Iran's potential to build atomic bombs from its growing stockpile of low-enriched uranium.

They have warned Iran it risks a fourth round of U.N. sanctions if it fails to help defuse concerns about its nuclear program. Iran insists the work is for the peaceful generation of electricity.

Western powers withheld substantive comment on Iran's demands for amendments to the pact.

U.S. Secretary of State Hillary Clinton signaled on Friday the United States would allow talks with Iran to play out before considering fresh sanctions.

Iran's clerical establishment agreed to talks with world powers after a disputed presidential election in June and its turbulent aftermath, which harmed the legitimacy of the country's leadership.

Some hardliners have criticized the establishment for succumbing to international pressure to accept the deal, which could prove a test of U.S. President Barack Obama's diplomatic outreach and his push for nuclear disarmament worldwide.