"Considering this information, make a conscious decision concerning travel, days out and family visits,” the health ministry’s spokesman tweeted.

Tehran’s bazaars were busy and its roads filled with cars as Iranians prepared for Nowruz, which starts on Friday.

The country has reported 18,407 confirmed cases of Covid-19 and 1,284 related deaths in the past month.

The government has closed schools, universities and shrines, and banned cultural and religious gatherings in an attempt to contain the spread of the disease, but it has not imposed lockdowns.

Image copyright Reuters

 Workers have been disinfecting streets in Tehran to try to prevent the spread of Covid-19

In a separate development on Thursday, Iran temporarily released an American citizen on medical grounds detained since 2018, US Secretary of State Mike Pompeo said.

Michael White, who is serving a 13-year sentence and whose family said he had cancer last year, is now in the custody of the Swiss embassy and will undergo medical testing and evaluation.

“The United States will continue to work for Michael’s full release, as well as the release of all wrongfully detained Americans in Iran,” Mr Pompeo said.

On Thursday, health ministry spokesman Kianoush Jahanpour announced 149 new deaths from Covid-19 in the past 24 hours and another 1,046 cases.

At the current rate, he tweeted, "50 new cases of infection are detected every hour and one death recorded every 10 minutes".

Mr Jahanpour appealed to Iranians to stay at home and not travel during the two-week public holiday for Nowruz, when many families get together to celebrate, in order to help contain the spread of the virus.

On Wednesday, Deputy Health Minister Alireza Raisi expressed dismay that some people were not taking the disease “seriously”.

Photographs showed many people were still shopping in Tehran’s bazaars and driving their cars in apparent violation of a religious ruling from Supreme Leader Ayatollah Ali Khamenei forbidding “unnecessary” travel.

Earlier, the Iranian judiciary’s spokesman announced that about 10,000 prisoners, half of them serving sentences for “national security offences”, would be granted amnesties by the supreme leader to mark Nowruz.

The amnesty aimed to “reduce the number of prisoners in light of the sensitive situation in the country”, Gholamhossein Esmaili said, without explicitly referring to the Covid-19 outbreak.

Amnesty International said it welcomed “the release of anyone detained as a prisoner of conscience" and called on the Iranian authorities to release all others in its jails.

The judiciary has already given 85,000 inmates two-week temporary releases in an effort to reduce the spread of Covid-19 through its crowded prisons.

Image copyright EPA

 Cafes in Egypt are closed from dawn until dusk

Many cases reported elsewhere in the Middle East have also been linked to Iran.

In Jordan, which has reported 35 cases of the Covid-19 virus, the army has begun imposing restrictions on access to the capital, Amman.

Soldiers at checkpoints on main roads into the city were only allowing through goods vehicles and people travelling on authorised business.

Egypt, where four people have died and 166 others have been infected, has ordered the closure of all cafes and shopping malls from dawn until dusk.

Saudi Arabia, which has reported 171 cases, has said it will cut government spending by 5%, or about $13.3bn, to offset the significant drop in global oil prices and the impact of the outbreak on its economy.