Francois Murphy, Parisa Hafezi

VIENNA (Reuters), – Monday’s meeting between Iran and world powers will be held in Vienna to discuss salvaging their 2015 nuclear accord. But with Tehran continuing to stick to its rigid stance, and Western powers becoming more frustrated, any hope of a breakthrough seems slim.

Diplomats believe that it is too late to revive the agreement, which the US President Donald Trump left in 2018 angering Iran, and disappointing the other countries involved, including Britain, France, Germany, China and France.

Between April-June, six rounds were held in indirect talks. Following a brief hiatus caused by Ebrahim Rashi, an extremist cleric, being elected Iranian president in June, the new round starts.

The demands made by Tehran’s new negotiation team are not realistic, according to Western diplomats.

The sanctions include the demand that all U.S.-imposed and European Union sanctions since 2017, even ones not related to Iran’s nuclear program, be removed. [nL8N2SI09H

In parallel, Tehran’s conflicts with the U.N. atomic watchdog, which monitors the nuclear programme, have festered.

Iran has pressed ahead with its uranium enrichment programme and the IAEA says its inspectors have been treated roughly and refused access to reinstall monitoring cameras at a site it deems essential to reviving the deal.

“If Iran thinks it can use this time to build more leverage and then come back and say they want something better, it simply won’t work. We and our partners won’t go for it,” U.S. envoy Robert Malley told BBC Sounds on Saturday.

He warned that Washington would be ready to ramp up pressure on Tehran if talks collapse.

Iranian officials have insisted in the run-up to Monday that their focus is purely the lifting of sanctions rather than nuclear issues. Highlighting that, its 40-strong delegation mostly includes economic officials.

“To ensure any forthcoming agreement is ironclad, the West needs to pay a price for having failed to uphold its part of the bargain. As in any business, a deal is a deal, and breaking it has consequences,” Iran’s top nuclear negotiator, Ali Bagheri Kani said in defiant column in the Financial Times on Sunday.

“The principle of ‘mutual compliance’ cannot form a proper base for negotiations since it was the U.S. government which unilaterally left the deal.”

Diplomats have said Washington has suggested negotiating an open-ended interim accord with Tehran as long as a permanent deal is not achieved.

Failure to strike a deal could also prompt reaction from Israel which has said military options would be on the table.

“The talks can’t last forever. There is the obvious need to speed up the process,’ Moscow’s envoy Mikhail Ulyanov said on Twitter (NYSE:).