Deal may be close on Iran sanctions

Strong signs emerged Saturday of a breakthrough in the nuclear negotiations with Iran over one of the most contested issues: sanctions.

"Instead of giving in to Iran's demand for an immediate suspension of sanctions, that will instead happen over three stages," CBS News State Department correspondent Margaret Brennan reported on the proposed compromise from Vienna, where the talks are taking place.

"As Iran starts to freeze its nuclear program, the U.S. and western powers will then peel back a set of the restrictions," Brennan said. "But none of this is going to happen as quickly as the Iranians had hoped."

According to Brennan, the sanctions proposal is a key component of an overall agreement on Iran's nuclear program.

"Iran's top negotiator, Javad Zarif, issued an 11th hour video appeal and said the two sides have never been closer," Brennan said. "But then he also said the U.S. needs to stop making demands, and that's likely a reference to the American stipulation that inspectors get access to all suspected sites, including military installations."

If an agreement can be reached, Brennan reported, it could herald a new era of cooperation between the U.S. and Iran.

"One Iranian top diplomat told me that if the Americans are willing to compromise on this, it could open the way for the U.S. and Iran to work together on common threats, including the fight against ISIS," Brennan said.