Iran has issued its first death sentence over the protests that have shaken the country's clerical leadership, the country's judiciary said.

The ruling likely marks the first death sentence in the trials of those arrested for participating in protests that have swept Iran over the past weeks demanding an end to clerical rule.

Another court in Tehran sentenced five others to prison terms of between five to 10 years for "gathering and conspiring to commit crimes against national security and disturbing public order".

A rights group has warned that other convicts risked being "hastily" executed.

Earlier this month, 272 of Iran's 290 politicians demanded the judiciary apply the death penalty, in "An eye for an eye" retributive justice against those who "Have harmed people's lives and property with bladed weapons and firearms".

The almost two months of protests sparked by the death of Mahsa Amini, who had been arrested by the morality police, have prompted authorities to unleash a crackdown that has led to thousands being detained.

Ms Amini was detained after allegedly violating the country's strict dress code for women.

Some have been charged with offences for which they could face the death penalty in a country that Amnesty International has said executes more people annually than any nation other than China.

During the subsequent crackdown, security forces, including paramilitary volunteers with the Revolutionary Guard, have killed more than 300 people, including dozens of children, according to the Oslo-based Iran Human Rights.

Iranian authorities said more than 40 security forces were also killed in the nationwide unrest.

Although the protests first focused on ending Iran's mandatory headscarf, or hijab, they have since transformed into one of the greatest challenges to the ruling clerics since the chaotic years following the 1979 Islamic Revolution.

More than 2,750 people charged over 'riots':

Mahmood Amiry-Moghaddam, the director of Norway-based NGO Iran Human Rights, said according to official information, at least 20 people are now facing charges punishable with death.

"We are very concerned that the death sentences may be carried out hastily," he said.

"The international community must send a strong warning to the Iranian authorities that implementation of the death sentence for protesters is not acceptable and will have heavy consequences."

On Sunday, Mizan and other local media also said the judiciary has charged more than 750 people in three provinces for involvement in "Recent riots".

More than 2,000 people had already been charged, nearly half of them in the capital Tehran, since the demonstrations began, according to judiciary figures.

The crackdown has also led to the arrest of dozens of activists, journalists and lawyers whose continued detention has caused an outcry abroad.

According to IHR, at least 326 people have been killed by the security forces in a crackdown on the nationwide protests.

This figure includes at least 123 people killed in the province of Sistan-Baluchistan, on Iran's south-eastern border with Pakistan.

Most of those were killed on September 30 when security forces opened fire on protesters after Friday prayers in Zahedan, the capital of Sistan-Baluchistan — a massacre activists have dubbed "Bloody Friday".

Those protests were triggered by the alleged rape in custody of a 15-year-old girl by a police commander in the province's port city of Chabahar.

A delegation from Iran's supreme leader Ayatollah Ali Khamenei expressed sadness and promised solutions in a weekend visit to Zahedan, official media said.

The city's police chief and the head of a police station had already been dismissed, local officials had already announced.

Sources | AFP / AP / ABC