For Amir Moghtader the waiting has become a torment. Uncertainty is the cause, but as the clock ticks down he still hopes there can be a nuclear deal for Iran.

"I don't know what the solution is, but the government should find it and it should benefit both sides," he says, parked at Argentine Square, a busy intersection for workers entering and leaving central Tehran.

The 52-year-old taxi driver, like all Iranians, has become accustomed to waiting. But while diplomats bargain abroad over terms that could end a 13-year crisis over the Islamic republic's nuclear programme, minds are filled with doubt and fear about the eventual outcome.

A pre-emptive announcement at talks in Vienna that a third deadline for a deal is likely to be missed on Tuesday has only added to the uncertainty.

Moghtader is tired of the struggle. He may not be in oil or finance, the two biggest industries affected by Western sanctions on Iran, but the economic fallout has hit him all the same.

"If I have to buy a spare part for my car, I have to pay the equivalent price in dollars, but what I get from my customers is rials," he says, alluding to inflation that has seen Iran's currency shed two thirds of its value since 2011, when the nuclear crisis began to engulf the economy.

"We are all under pressure. I hope there can be a deal."

Despite agreeing the outlines of an agreement on April 2, the final talks between Iran and six powers led by the United States on turning it into a binding accord have hit difficulties.

A deal would lift sanctions, paving the way for foreign investment to flow back, in exchange for curbs on Iran's nuclear activities.

But an insistence from the West for access and inspections at nuclear and military sites, to verify that Iran's nuclear activities are peaceful, seems to have thrown an agreement into jeopardy again.

Iran's supreme leader Ayatollah Ali Khamenei, just four days before the current talks started, ruled military inspections out.

And days later Iran's lead negotiator in the talks said some of the world powers had changed their positions on what was agreed in April, by recently making new demands.

- Fears for oil sector -

Brinkmanship at a crunch point in negotiations is just politics to Ahmad Asgari, an oil and gas consultant, but the final outcome is pivotal.

A deal could bring a step change to his industry. Failure in the talks could finish him.

"My fear is that if there is no deal my company will shut down," he says. "We cannot endure this situation anymore. I have spent all my savings."

Having once employed 100 people, only 20 remain on the payroll at the Association of Petroleum Industry Engineering and Construction Companies (APEC), where Asgari is managing director.

He says sanctions have meant very few projects in the past eight years, with the most recent restrictions on banking in 2012 drying up finance and cashflow and hindering imports of vital equipment.

"Iran has huge gas reserves in the south but we can't develop them and take advantage," says Asgari.

"But if the embargo is removed, the experts we need will come back, we will receive funds and we will create jobs and perhaps persuade our youth that they do not need to emigrate."

The economic divide in Iran -- a decade-long boom from the early 1990s bolstered the middle class but is now a distant memory -- has widened as sanctions have hit home.

Jahangir Raafat is one of the more fortunate, riding out hard times.

An oncologist, he can afford to educate his children abroad, and with a full waiting room of 30 patients, business has never dwindled.

"Everybody wants the sanctions removed, things would get better," he says. "But we can manage if there is no deal. Of course, bright young people will still want to leave. We can't stop them."

US says there's a way to give UN access to Iran sites
Vienna (AFP) June 29, 2015 - Global powers negotiating with Iran have put forward proposals to give the UN atomic watchdog access to all suspect Iranian sites as part of the outlines of a deal, a senior US official said Monday.

"We have worked out a process that we believe will ensure that the IAEA has the access it needs," the administration official told reporters.

"The entry point isn't we must be able to get into every military site, because the United States of America wouldn't allow anybody to get into every military site, so that's not appropriate," the official said.

Another US official later said the proposals were part of an April 2 deal agreed in Switzerland "the details of which are being negotiated now."

The Islamic republic has so far refused to give the International Atomic Energy Agency (IAEA) access to sensitive sites.

"There are conventional purposes, and there are secrets that any country has that they are not willing to share," the first American official said.

"But if in the context of this agreement... the IAEA believes that it needs access and has a reason for that access, then we have a process to ensure that that is given," the official said.

Iran has denied seeking to arm itself with nuclear weapons, but the IAEA has so far been unable to verify that its atomic programme is entirely peaceful.

The US official, who asked not to be named, said Washington had long insisted that if the IAEA felt it needed access to a suspect site "then they should be able to get it".

"If that happens to be a military site then that should be available," the official said, adding the IAEA had an "institutional responsibility" to explore what the possible military dimensions of Iran's nuclear programme may have been.