Extension of Iran talks deadline 'highly probable': diplomat

Says there is very little progress on the issue of uranium enrichment

An extension of Sunday's deadline to strike a nuclear deal between Iran and world powers is now "highly probable," and by months not weeks, a Western diplomat said today.

"As it's highly improbable that we will finalise in Vienna before the weekend, it is highly probable that there will be a wish to continue to negotiate in the coming months," the diplomat said on condition of anonymity on the sidelines of talks in Vienna.

Just extending "by weeks doesn't make much sense," the envoy said. "It is soon August ... There will have to be a break."

He added that following two days of intensive talks between US Secretary of State John Kerry who has now left Vienna and his Iranian counterpart, all focus was now on the terms of the extension.

This could even be agreed before the weekend, he said.

"We hope to have left here before (the weekend)... Since we are talking about a rollover."

He added that there had been some progress in the talks, but that on the key issue of uranium enrichment, Iran's position has shifted "very, very, very little".

"We cannot say that things are going in the wrong direction, they are going pretty much in the right direction. But on the biggest and most difficult issue (enrichment), we are still far apart," he said.