Iranian Foreign Minister Mohammad Javad Zarif
Iranian Foreign Minister Mohammad Javad ZarifReuters

Iran’s Foreign Minister Mohammad Javad Zarif said on Saturday that a deal on his country’s nuclear program can be reached only if global powers stop pressuring Tehran.

"If the Western countries want to negotiate with the Islamic Republic of Iran, they must make a political decision, which for some could be difficult, and stop with the pressure," Zarif told Iranian state television, according to the AFP news agency.

His comment came as Iran's deputy foreign minister Abbas Araqchi prepared for talks in Geneva Sunday with the so-called P5+1 group of global powers.

Following an interim accord in November 2013, two deadlines for a final deal have been missed, and now a third one is looming on July 1.

Araqchi, who has spent three days meeting with senior U.S. officials and has also met with Russian officials in preparation for Sunday's talks, told the Fars news agency a deal would depend on Washington showing "good will".

"We remain hopeful, and I think that if the other side has the necessary good will and determination it will be possible to reach a deal," he said, while acknowledging that "problems, chasms and differences also exist."

A Western source close to the talks however said the talks did not seem to be moving forward significantly and that the biggest stumbling block was on the Iranian side.

"The Iranians have not yet made enough gestures to enable us to reach a good deal that would ensure a substantial reduction of their residual (uranium) enrichment capacity, so we collectively can be assured they don't have the technical capacity to rapidly develop a nuclear bomb," he told AFP.

The source argued that any deal needed to ensure that Iran's "breakout capacity" for making a nuclear bomb would be at least one year to give the international community enough time to act.

If the global powers go along with "a weak deal, that would send a disastrous signal to the rest of the world on the issue of proliferation," he added.

This week, U.S. Secretary of State John Kerry and Zarif met in Geneva and held what was described as “intensive talks” on Tehran's disputed nuclear program.

Zarif also went to Berlin this week to meet his German counterpart Frank-Walter Steinmeier, who stressed that the negotiations had entered a "decisive phase" and urged all parties to "leave nothing undone to reach the solution that has eluded us in recent years."

Iran's top diplomat also met in Paris with his French counterpart Laurent Fabius, who raised "the significant questions that remain to be solved", the French foreign ministry said.

Before the talks were extended until July, Iran was toughening its stance, with Araqchi saying he sees no prospect for a deal unless the other side abandons its “illogical excessive demands”.

A senior Iranian official followed those comments by declaring that Iran will demand that all Western sanctions be lifted as part of a final deal, rejecting an American proposal of a gradual lifting of sanctions.