TEHERAN (AFP) - While many residents in Iran's capital are taking advantage of loosened Covid-19 controls, some worry about a new spike in infections in what remains the Middle East's deadliest virus epicentre.

"The line of fools," muttered shopkeeper Manouchehr, peering disdainfully at a queue of customers outside a foreign currency dealer in the Sadeghieh district of western Teheran.

Many in the long line stood close to one another and did not wear masks.

A traffic policeman told AFP such queues have appeared regularly ever since the money changers re-opened. People rarely observe basic anti-contagion protocols, he complained.

The government began paring back coronavirus controls outside Teheran on April 11, arguing that the economy - already sagging under punitive US sanctions - needed to get back to bare bones operations.

It allowed small businesses to reopen in the capital a week later, before permitting malls to welcome customers on April 21 and barbers on Wednesday.

At 802, declared daily infections in Iran on May 2 reached their lowest level since early March.

But this critical daily number has since begun resurging, breaching 1,500 on Saturday to take the country's total number of confirmed infections beyond 106,000.

'ENDANGERING OUR LIVES'

The capital's streets, bazaars and malls are now bustling after being nearly deserted for weeks after the bulk of control measures were imposed in March.

Milad, a shopkeeper in a mall, was conflicted about the easing of movement restrictions.

"All these customers coming in will endanger our lives - us who are forced to come" to work, he said.

The mall gets very busy in the evenings, noted the 22-year-old, who did not have any protective equipment.

The Covid-19 respiratory disease has killed nearly 6,600 people in Iran since the first two fatalities were reported in the city of Qom on Feb 19, according to authorities.

Deputy Health Minister Iraj Harirchi has called Teheran the country's "Achilles heel" in the fight against the virus.

The city's eight million residents are densely packed together and it is a magnet for hundreds of thousands of workers from other provinces.

The government moved to ease restrictions even as Teheran remained at red on its colour graded risk model - white denoting low risk, yellow medium and red high risk.

Schools, universities, cinemas and stadiums remain closed to contain the spread of the virus.

'THEY DON'T CARE'

"People being careful made infections drop, but as soon as the disease was deemed less of a concern, we saw cases grow," said Masoud Mardani, an infectious disease expert at the health ministry.

The rise is "partly due to the reopening (of businesses) and people going out shopping," he told the semi-official ISNA news agency, while also citing an increase in travel in Tehran province.

Health officials have vowed to re-impose stringent measures if the number of cases continues to climb.

But many Iranians remain adamant that they have to work to avoid financial ruin.

"Life costs money," said Hamed. "People have to go to work since this virus has been with us for about three months now." The 22-year-old was among those out on the streets without a mask, deeming such protection "largely ineffective".

He had travelled over 150km from Qom to Teheran for banking business for the private firm that employs him.

It is a trip he has to undertake every few days and says he cannot refuse for fear of losing his job.

A few streets away, pedestrians were shopping for fresh vegetables and dried fruit - mostly women or older men, but this time, mainly in masks.

"I think maybe only half the people follow health protocols" across the capital as a whole, said Zahra, a 30-year-old accountant.

"Either people don't care or don't have the patience" to wear a mask, she said.

Mohammad, a former building contractor, complained that masks were expensive and in short supply.

A disposable surgical mask can cost from 49,000 rials (30 US cents, using the unofficial rate) to 10 or 15 times that amount for the better quality durable coverings.

"They should have given them to people for free," said the mask-less 58-year-old.

But Mohammad's biggest gripe was overcrowding on buses, where red crosses marked on half of the seats to maintain social distancing are routinely ignored.

He said he was outraged to see a bus with "40 people on it" during his morning commute and urged authorities to increase services.