TEHERAN (NYTIMES) - When Iran began to reopen late last month, commuters packed subways and buses, young people lined up for takeout hamburgers and pizza, and traffic snarled highways. Shoppers crowded the traditional bazaars of Isfahan and Tehran. Worshippers resumed communal prayer at mosques during Ramadan evenings.

Three weeks later, the country has been hit by a new surge of coronavirus cases, according to health officials in some of the eight provinces where the numbers have spiked again. Health experts had predicted this would happen when the government made the call to ease restrictions in late April.

Iran, an epicentre of the outbreak in the Middle East, reopened without meeting the benchmarks recommended by health experts, such as ensuring widespread testing and contact tracing was in place, and recording a steady drop in cases for at least several weeks.

The central government has claimed for weeks that Iran was prevailing against the pandemic. But in reopening the country, President Hassan Rouhani said the battle could not fully succeed independent of salvaging the economy, which was being pummelled by US sanctions even before the virus hit.

The south-eastern province of Khuzestan, home to the country's oil and petrochemical industries, reported a 300 per cent increase in new cases since the province reopened in late April, according to its governor.

On Friday, Khuzestan locked down 16 of its cities at least until Monday. Local health officials said on Sunday that 715 people had tested positive for coronavirus in the previous 24 hours.

Other provinces that are reporting alarming surges include Isfahan, Fars, East Azerbaijan, Khorasan, Lorestan, Hormozgan and Sistan Baluchestan, according to the Health Ministry and local governors.

"The situation is extremely dire," Alireza Bahadori, mayor of the city of Behbahan in the hard-hit Khuzestan, said in a video circulating on Iranian media.

Hossein Farshidi, the top public health official in Hormozgan, called the surge in his southern province "extremely dangerous and worrisome".

The cries of alarm from local officials were at stark odds with the central government's claim that Iran has the virus under control.

"It's a source of pride that Iran has managed to not only reopen businesses by observing protocols but also reactivate its mosques and religious centers - and also maintain a steady decline of the disease," Rouhani said on Friday, according to official media.