Iran nuclear talks resume as U.S. seeks to stop Islamic Republic "moving forward" as 1st step

GENEVA Six world powers are dangling the prospect of easing some sanctions against Iran if Tehran agrees to curb work that could be used to make nuclear weapons.

Talks resumed Thursday between Iran and the six -- the United States, Russia, China, Britain, France and Germany.

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The last round three weeks ago reached agreement on the framework of what to discuss. The two sides now want to start a process meant to culminate in limits on Tehran's potential ability to make nuclear weapons, in exchange for easing of sanctions crippling Tehran's economy.

Before the talks, Iranian Foreign Minister Mohammed Javad Zarif met with top EU diplomat Catherine Ashton, who is convening the meeting. Ashton spokesman Michael Mann said the two had good discussions.

A senior Obama administration official said on the eve of Thursday's meetings that the goal was to reach an "initial understanding that stops Iran's nuclear program from moving forward for the first time in decades, and that potentially rolls part of it back."

In exchange, the official said in exchange, the U.S. and its partners were prepared to offer "limited, targeted, and reversible sanctions relief."

The official cautioned, however, that there was no interest from Washington in "touching the core architecture of the Iranian sanctions regime in this first step in any way. And if Iran does not live up to its obligations under the initial understanding, or if we cannot get a comprehensive agreement finalized, any economic relief we will have given Iran can, in fact, be reversed."

Iran denies any interest in nuclear arms.