The United Nations on Tuesday assailed Iran for the Islamic Republic's increasingly harsh attacks on protests that were sparked by the death of a 22-year-old Kurdish woman in the custody of the country's morality police.

More than 300 people, including around 40 children, have been killed during two months of protests, often in street clashes across the country. Iran has said that 46 members of its security forces have been killed, but the government has provided no further accounting of the death toll.

'U.N. human rights chief Volker Tuerk says the rising number of deaths from protests in Iran, including those of two children over the weekend, and the hardening of the response by security forces, underline the critical situation in the country,' spokesman Jeremy Laurence told reporters in Geneva.

'We urge the authorities to address people's demands for equality, dignity and rights, instead of using unnecessary or disproportionate force to suppress the protests,' he said. 'The lack of accountability for gross human rights violations in Iran remains persistent and is contributing to the growing grievances.'

Tehran has blamed foreign enemies and their agents for abetting the protests, one of the strongest challenges to the Islamist leadership of the country since the 1979 revolution. Iran's soccer team, in a show of support for the demonstrators, refused to sing the country's national anthem at the start of its first match at the World Cup tournament in Qatar on Monday.

The protests started soon after the death in mid-September of Mahsa Amini, which Iranian authorities attributed to a heart attack. She had been detained for allegedly not properly covering her hair with a hijab. Amini's family says she had no history of heart trouble.

Later this week, the U.N. Human Rights Council in Geneva is holding a debate on the protests that witnesses and victims are expected to attend.

One proposal to be discussed at the session would seek to establish a fact-finding mission on the authoritarian crackdown.

U.N. spokesman Laurence said, "Significant numbers of security forces have also been deployed in recent days. Overnight, we received reports of security forces responding forcefully to protests in several mainly Kurdish cities, including Javanrud and Saqqez.'

Since the beginning, he said, 'Protesters have been killed in 25 of Iran's 31 provinces, including more than 100 in Sistan and Baluchistan."

Laurence voiced particular concern at 'the authorities' apparent refusal to release the bodies of those killed to their families or making the release of their bodies conditional on the families not speaking to the media or agreeing to give a false narrative on the cause of death.'

He also criticized the government for the thousands of people 'detained throughout the country for joining peaceful protests,' saying that a growing number of Iranian celebrities and sports stars who had voiced support for the protests were being summoned and arrested.

Especially alarming, he said, was that six people connected to the protests had been handed death sentences.

'We call on the authorities to release all those detained in relation to the exercise of their rights ... and to drop the charges against them,' Laurence said. 'Our office also calls on the Iranian authorities to immediately impose a moratorium on the death penalty and to revoke death sentences issued for crimes not qualifying as the most serious crimes under international law," he said.

Some material in this report came from Reuters and Agence France-Presse.