Kerry seeks breakthrough in troubled Iran nuclear talks

He however added that discussing an extension in deadline was not on the table

Troubled Iran nuclear talks enter the make-or-break endgame today as US Secretary of State John Kerry and his Iranian counterpart seek a breakthrough just days ahead of a deadline.

Meeting in Vienna in a final round of talks between Iran and six world powers before Monday's deadline to agree a deal, the differences are few in number but of major significance.

Speaking in Paris yesterday before flying to Vienna, Kerry said however that the possibility of putting more time on the clock -- as happened in July with an earlier deadline -- was not on the table.

"We are not discussing an extension. We are negotiating to have an agreement. It's that simple," Kerry said.

He added however that the United States and all the other powers were 'concerned about the gaps'.

Britain's Foreign Secretary Philip Hammond had said on Wednesday that he was 'not optimistic' the deadline could be met, suggesting that the best hope was for another extension.

"I think if we make some significant movement, we may be able to find a way of extending the deadline to allow us to get to the final deal," Hammond said in Riga.

Russia's main negotiator in the talks, Sergei Ryabkov, said yesterday that the talks were being held in a 'tense atmosphere' and that agreeing the mammoth accord would be tough.

"In the current situation it will be very difficult to get a deal unless there is a new spirit," Ryabkov was quoted as saying by Russian agency RIA Novosti.

Iran's speaker of parliament Ali Larijani meanwhile told Iranian media, "We are constantly cooperating (but the other side) is raising the tone."

He added, "We hope that the other side will behave in a rational manner... And won't take the wrong path."

French Foreign Minister Laurent Fabius, who together with Hammond was expected in Vienna today, said there remained 'major differences'.

"We hope that they can be bridged but that depends to a very large extent on Iran's attitude," Fabius said at a joint news conference with Kerry in Paris.

Iran's Foreign Minister Mohammad Javad Zarif believes however that the onus is on the other side, urging them not to make 'excessive demands'.