Iran and world powers have reportedly locked horns in an intense second day of nuclear talks in Geneva.
According to AFP, Tehran said on Thursday that "no progress" was made towards clinching a long-awaited breakthrough deal.
Both sides, seeking to end the standoff over Iran's nuclear program after a decade of rising tensions, stressed however that the talks in Geneva were detailed, serious and constructive.
The United States, China, Russia, Britain, France and Germany - known collectively as the P5+1 - are asking Iran to freeze parts of its nuclear program for six months in exchange for some relief from the sanctions that have hurt the Iranian economy.
This hoped-for "first phase" deal would ease tensions while Iran and the six powers hammer out a final accord to put an end to fears that Tehran is seeking to build an atomic bomb.
However, Iran's delegation chief said after meetings lasting a total of four and a half hours between Foreign Minister Mohammad Javad Zarif and P5+1 negotiator Catherine Ashton that "no progress" had been made in narrowing differences.
Abbas Araqchi, quoted by the Mehr news agency, did not elaborate, but a European source gave a more upbeat assessment.
"We are making progress. There fewer points in brackets (in the draft agreement)," the source said, according to AFP.
"But obviously the remaining issues are the hardest ones... Tomorrow (Friday) will be important."
The proposed accord includes suspending uranium enrichment to 20 percent purity as well as measures reducing uranium stockpiles and tighter UN inspections.
Similar talks two weeks ago came close to succeeding, but no agreement was reached after France insisted that the proposed deal did not go far enough in securing guarantees on Iran's uranium enrichment.
French Foreign Minister Laurent Fabius said Thursday that the text being debated with the Iranians was "supported by all six" world powers, according to AFP.
Israel has repeatedly stressed that the proposed agreement is a “bad deal,” leading to tension with the United States. In fact, the latest report on the tension between the U.S. and Israel has quoted a top White House official as having declared that Israel’s proposal that Iran totally dismantle its nuclear capacity would likely lead to war.
On Thursday, Prime Minister Binyamin Netanyahu declared once again that Iran must not obtain nuclear weapons and that Israel will not allow it to do so.
According to recent reports, Israeli leaders are not relying on diplomacy alone, and are also working alongside Arab leaders on a plan to attack Iran if its deal with the West fails to yield serious change. Several Israeli leaders have stated that Israel could act alone on Iran.