Deadline in Iran nuke talks likely to be extended

Negotiations between Western powers and Iran to reach a permanent agreement on the future of Tehran's nuclear ambitions are likely to be extended beyond the July 20 deadline, a senior U.S. official and a Western diplomat told CNN on Tuesday.

The sources, who did not speak for full attribution, said the United States and its partners in the negotiations -- Britain, France, Germany, China and Russia -- had not started talking about an extension with the Iranians.

But there are a number of potential time frames being discussed among the United States and its partners, ranging up to six months, the sources said.

Secretary of State John Kerry said on Tuesday in Vienna the negotiations have not yet bridged some "very real gaps."

Kerry told reporters there had been "tangible progress on key issues," but negotiators have yet to arrive at a "workable formula."

He said he would return to Washington to consult with the White House and lawmakers on options for moving forward, including whether to extend the talks beyond the deadline.