Major powers seeking to negotiate an end to Iran's suspected pursuit of nuclear weapons on Friday signaled their openness to renewed talks with Tehran but diplomats said the powers remain divided on their approach.
EU foreign policy chief Catherine Ashton, who represents the group, issued a statement making clear that a diplomatic path remains open to Iran despite tougher sanctions and fresh speculation of a military strike on its nuclear facilities.
The group, known as the P5+1 and as the EU3+3, includes Britain, China, France, Germany, Russia and the United States.
"The EU3+3 has always been clear about the validity of the dual track approach," Ashton's spokesperson said in a statement that included her Oct. 21 letter. "We are waiting for the Iranian reaction."
The release of the statement and the letter itself appeared be an effort to demonstrate that the major powers are willing to talk to Iran, while reiterating their demands that Tehran must return to the table willing to talk about its nuclear program.
It also appeared to reflect frustration at recent Iranian statements hinting at a willingness to return to the table but Tehran's failure to formally respond to the letter and commit to discussing the nuclear program in earnest.
Western nations suspect Iran is pursuing nuclear weapons but Tehran says its nuclear program is for civilian energy purposes.
One diplomat said Iran had been sending mixed signals on whether it might be willing to return to talks in the face of tighter U.S. sanctions focused on its crude oil exports and the possibility of a European Union petroleum embargo.
"This is a way to ensure that our offer is absolutely clear," said the diplomat, adding that the central point was to make clear that "we are prepared to sit down with you if you are prepared to demonstrate serious intent."
There have been signals in recent weeks that Iran might be willing to hold a new round of talks about its nuclear program.
French President Nicolas Sarkozy said on Friday time was running out to avoid a military intervention in Iran and he appealed to China and Russia to support new sanctions to force Tehran to negotiate over its uranium enrichment program.
Friday's statement follows pleas by Iran's Arab neighbors for major powers to scale back an intensifying confrontation with Tehran that has sparked an Iranian threat to close the Strait of Hormuz and has raised fears of regional conflict.
Diplomats said that major powers are divided over what incentives to offer Iran if talks resume and whether to allow it to keep enriching uranium at lower levels.
If the Iranians were willing to sit down, the question would then become how the major powers, known as the P5+1 and as the EU3+3, might approach Iran during any such negotiations, notably on any "confidence-building measures."
"There is no agreement inside the P5+1 on how such confidence-building measures should or should not be presented to the Iranians," said one diplomat.
A central issue is whether the group might ask Iran to cease enriching uranium to the higher level of 20 percent but allow it, at least for a time, to continue enriching at lower levels - a stance partly at odds with the group's past positions.
Uranium enrichment is a process that at low levels can yield fuel for nuclear power plants or, if carried out to much higher levels of purity, can generate fissile material for bombs.
Multiple UN Security Council resolutions have called on Iran to suspend its uranium enrichment and related activities and the P5+1 has taken the view that it must suspend such activities during any serious negotiation.
To permit Iran, even for a period, to enrich at lower levels would be something of a concession by the P5+1, although it has previously offered a temporary "freeze-for-freeze" in which Iran would halt expansion of its nuclear program and the major powers would not pursue additional sanctions.
Asked why some members of the group might be willing to let Iran continue to enrich at lower levels, at least for a period, one diplomat said it reflected a desire to give diplomacy every possible chance to succeed.
"That really is the crux of it. You want to be able to say that you pursued every option diplomatically to try to get Iran to halt its program," he said.
A senior Obama administration official told Reuters that if talks were to resume, the group would have a common stance.
"If the Iranians accept the offer of the P5+1 to have talks on the basis of High Representative Ashton's October letter, we fully expect a unified P5+1 approach to the talks," the official said.