Iran's Isfahan Uranium Conversion Facilities in February 2007.

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NEW: Russian Foreign Minister expresses hope for a compromise with Iran

Proposed deal would cover every aspect of Iran's nuclear program, U.S. official says

It would also "extend the breakout time" Iran would need to achieve a nuclear weapon

CNN  — 

Undersecretary of State Wendy Sherman is scheduled to lead the American delegation at the round of talks next week in Geneva.

The statements by Foreign Minister Sergey Lavrov broadcast on Russian TV come just days before negotiators meet in Geneva, Switzerland, to discuss details about Iran’s nuclear program.

“Our common impression is that there is a very good chance now which should not be missed,” Lavrov said in remarks broadcast on state-run TVC.

The assessment, Lavrov said, came out of recent talks with the European Union’s foreign policy chairwoman, Catherine Ashton.

That tone was echoed earlier in the week by the United States.

The United States and other countries are “getting close” to an interim deal with Iran that would prevent its nuclear program “from advancing, and roll it back” in key areas, a senior U.S. administration official said Friday.

Such a deal would “extend the breakout time” that Iran would need to achieve a nuclear weapon and “shorten the time to notice if they tried,” the official said on condition of anonymity.

The proposed deal covers every aspect of Iran’s nuclear program, including uranium enrichment, uranium stockpiles and all nuclear facilities including military ones, the official said.

The deal will be on the table during the next round of talks in Geneva.

“I don’t know if we’ll reach an agreement. I think it is quite possible that we can. But there are still tough issues to negotiate,” the official said.

The United States, along with the four other permanent members of the U.N. Security Council and Germany – the so-called P5+1 – came close to a deal during talks with Iran last week in Geneva, but the discussions ended with both sides blaming each other for the lack of an agreement.

The P5+1 is “completely and totally unified” on the current outlines of the proposed deal, the official said.

It is widely believed that Iran harbors aspirations to produce nuclear weapons. Repeated findings by U.N. weapons inspectors indicate that the country appeared to be conducting nuclear weapons research.

Iran has always maintained that its nuclear program is for purely peaceful purposes. Even though Iran has denied working toward nuclear weapons, it has said it will not submit to any plan that would totally eliminate its nuclear program.

CNN’s Jim Scuitto, Tom Watkins and Sara Mazloumsaki contributed to this report.