Iran is to pardon 10,000 prisoners, including some charged with political crimes, in honour of the Iranian new year on Friday, according to state TV.

It was not stated whether the pardons would include the British-Iranian aid worker Nazanin Zaghari-Ratcliffe – who was freed on Tuesday for two weeks as part of a separate programme under which 85,000 have temporarily been released because of coronavirus.

Iran is the Middle Eastern country worst affected by the pandemic, with a death toll of 1,284, the highest after Italy and China. Health ministry spokesman Kianoush Jahanpour said that Covid-19 was killing one person in the country every 10 minutes, while 50 new infections were detected each hour.

Judiciary spokesman Gholamhossein Esmaili made no explicit reference to coronavirus but said in a statement that the early releases aimed to “reduce the number of prisoners in light of the sensitive situation in the country.” Previous pardons, which last year freed 50,000 for new year, have largely not applied to those held for political offences.

“A large number of prisoners who have been temporarily freed do not need to return to jail after the leader’s pardon,” the statement said.

“Those who will be pardoned will not return to jail … almost half of those security-related [political] prisoners will be pardoned as well. The unprecedented point is that the pardon also includes the security-related prisoners with less than five-year jail sentences.”

Richard Ratcliffe said his wife was technically eligible for a pardon since her sentence was for five years, but he could not be certain she would remain at liberty. “It is something we will explore when the judicial officers reopen after the Iranian new year in a fortnight,” he said. “We must not set our hopes too high since she is viewed as a special case, and much may depend on the diplomatic climate, including the help Iran is being given by Britain to deal with Coronavirus”.

Even if Zaghari-Ratcliffe’s two-week furlough is extended, there is no guarantee she would be allowed to leave Iran to join her husband and daughter, Gabriella, in London.

There was also no word about British-Australian academic Kylie Moore-Gilbert, or another British Iranian dual national, Anoosheh Ashoori. Both are serving 10-year sentences.

Terry Waite, the former envoy to the Archbishop of Canterbury, wrote to the Iranian supreme leader, Ayatollah Ali Khamanei, urging him “to show the true spirit of Islam, and show mercy and compassion by releasing Ashoori to his family”. Waite played a key role in releasing Iranian hostages in the 1980s.

The UK foreign secretary, Dominic Raab, speaking to the UK foreign affairs select committee, described Zaghari-Ratcliffe’s release as “a partial success”, and said he did not wish to disclose the content of a call between himself and the Iranian foreign minister Javad Zarif on Tuesday.

The Iranians have been stepping up a campaign to put international pressure on the US to soften its sanctions regime if only to allow extra medical and humanitarian aid to reach the country. Officials have said they face severe shortages, and the level of poverty in the country is one reason they dare not impose a citywide lock-down in Tehran, as it would deprive the poor of any income.

The Democrat presidential candidate Bernie Sanders called on the US government to lift the sanctions to allow medical relief into Iran, but the Trump administration instead stepped up sanctions, in part believing that the relentless pressure would force the regime to hand over US political prisoners.

A US military veteran imprisoned in Iran was on Thursday released for medical reasons on condition that he remains in the country. A lawyer for Michael White said the furlough was related to pre-existing medical conditions and not directly related to the coronavirus outbreak.

A total of 18,407 people have contracted the disease in Iran, with 1,046 new cases confirmed in the last 24 hours. The figures were broadly in line with the previous day. Five former health ministers in Iran have urged the government to limit inter-city travel and close non-essential businesses in order to reduce the pace of new infections in the country.

The former ministers, all medical doctors by profession, argued in a letter to President Hassan Rouhani that one month after the start of the epidemic, “The trend of the disease and its consequences continue to show an upward trajectory and it has not declined in any part of the country.”

In their letter, published by Fars news agency, the ex-ministers spoke of “dozens of people” dying in Iran daily, and warned the government that the disease must be controlled. They urged the government to take “fundamental steps” and reduce contact between citizens.

Authorities have urged Iranians to stay at home and avoid travelling during the Nowruz new year, which begins on Friday. Iran has not imposed quarantine measures, but has urged the population to take the virus “seriously”.