Informed sources in Vienna announced that French Foreign Minister Laurent Fabius has grown angry with the approach of his US counterpart John Kerry and for the same reason he had a verbal dispute with Zarif

Informed sources in Vienna announced that French Foreign Minister Laurent Fabius has grown angry with the approach of his US counterpart John Kerry and for the same reason he had a verbal dispute with Iran's top negotiator Mohammad Javad Zarif.

Informed French sources, speaking on conditions of anonymity, told the Arabic-language Lebanese Al-Ahd news website that Fabius is discontent with the American team of negotiators, adding that he had a dispute with Zarif after he felt the negotiations were going too smooth, Fars news agency reported.

"Fabius is angry with the US negligence towards France in the nuclear talks and that has resulted in his anger," the sources added.

Late on Thursday night, diplomatic sources in Vienna cautioned that the western powers have toughened their stances after the US lost a self-imposed deadline for a deal with Iran and are raising even more demands from the Iranian team, Fars said.

The source said the western parties to the talks with Iran, specially the US, have in the last few days raised excessive demands beyond earlier agreements, making the road to a draft final nuclear deal even more bumpy.

The source said Iran is determined to clinch a deal and it has shown much flexibility on this path, but the US-led West has been raising excessive demands and shows "fading respect for its earlier agreements with Iran".

"They have started psychological operations and are playing the blame game to make Iran surrender to their increasing demands or wait to be portrayed as the party to blame for the potential failure of the talks," the diplomat added.

The source also strongly rejected the allegations made by certain western media outlets that the Iranian team is referring the opposite sides' proposals or the draft text to Tehran to ask for permission, reiterating that "the Iranian team of negotiators have been vested with full authority to strike a deal on behalf of the Islamic Republic of Iran based on the country's specified redlines, and does not need to refer anything to Tehran."

The diplomat strongly warned the western powers' approach in the last few days "is pushing the talks into a deadlock".

Earlier on Thursday night, Iranian Foreign Minister Mohammad Javad Zarif left a new post on his Twitter account, saying, "We're working hard, but not rushed, to get the job done. Mark my words; you can't change horses in the middle of a stream."

Minutes later, US Secretary of State John Kerry also appeared in front of the cameras in Vienna, and said, "Despite all the agreements we have made so far, some tough issues have remained unresolved."

"These issues should be resolved. And tough decisions should be made," he added, and continued, "We want a deal that stands the test of time."

Kerry said the negotiations are not open-ended, but he didn't say how long the talks would last.