U.S. & World

WASHINGTON (CBS) ― In a break with past Bush administration policy, a top U.S. diplomat will for the first time join colleagues from other world powers at a weekend meeting with Iran's chief nuclear negotiator, CBS News has confirmed.

William Burns, America's third highest-ranking diplomat, will attend talks with the Iranian envoy, Saeed Jalili, in Geneva on Saturday. Burns will join European colleagues in talks aimed at persuading Iran to halt activities that could lead to the development of atomic weapons, a senior State department official told CBS News on Tuesday.

Official contacts between Iran and the United States are extremely rare and although Washington is part of a six-nation effort to get Iran to stop enriching and reprocessing uranium, the administration has shunned contacts with Tehran on the matter.

The senior U.S. official, who spoke on condition of anonymity ahead of a formal announcement of Burns' plans expected on Wednesday, acknowledged a shift in the administration's approach but stressed that Burns would not meet Jalili separately and would not negotiate with him.

"This is a one-time event and he will be there to listen, not negotiate," the official said.

Nevertheless, CBS News foreign affairs analyst Pamela Falk says the Bush administration's decision to send Burns "represents a departure from the President's policy and a decision to negotiate aggressively with the Iranians on the nuclear issue, without the precondition that Iran first suspend uranium enrichment."

The meeting in Geneva is being led by European Union foreign policy chief Javier Solana, who is seeking a definitive answer from the Iranians to an offer of incentives that the five permanent members of the U.N. Security Council and Germany presented last month.

The package of incentives was accompanied by a letter from U.S. Secretary of State Condoleezza Rice and the foreign ministers of the other five countries and sets out a scenario in which Iran would get a temporary reprieve from crippling economic and financial sanctions in exchange for freezing its enrichment activities.

Preliminary negotiations over a permanent halt could then begin, although the United States would not join them until after Iran agrees to fully suspend uranium enrichment, which can produce the fuel needed to make nuclear bombs.

The proposal "gives the Iranians a face-saving way out of the issue by recognizing Iran's right to uranium enrichment for peaceful purposes, gives them support for construction of a light water reactor, support for Iran's admission to the World Trade Organization and the lifting of economic sanctions," says Falk. "And it may calm Israel's fear that Iran will continue its nuclear program to the point where it could develop nuclear weapons."

"Incentives to the Bush administration and to Iran to work out a deal are strong: U.S. financial markets have reeled at the possibility of a new military confrontation and Iran's economy has suffered from the isolation," of strict economic sanctions, adds Falk.

An administration official said "the sanctions are having some effect... they're feeling some heat," reports CBS News correspondent Charlie Wolfson. The administration official noted that some Europeans have imposed additional restrictions of their own and some deals made with European companies have been cancelled.

The senior U.S. official said Burns would be at the meeting with Jalili to demonstrate the unity of the countries making the offer of incentives but also to reinforce Rice's signature on the letter from the foreign ministers.

But Burns will also "reiterate that our terms for negotiations remain the same: Iran must suspend its enrichment and reprocessing activities," the official said.

Iran last week responded to the offer through the European Union but indicated that it has no plans to stop enriching uranium - a key demand. The process can be used to generate electricity or build nuclear weapons.

Iran says its nuclear program is purely energy-related, but the United States accuses it of trying to develop atomic weapons, prompting sanctions.

(© 2009 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)