The death of Mahsa Amini triggered months of some of the biggest protests against the Islamic Republic's Shiite clerical rule ever seen and drew international condemnation.

Mahsa's father was warned against marking the anniversary of his daughter's death, the Kurdistan Human Rights Network says, and the family was not able to hold a planned vigil at her graveside.

The latest hangings double the number of executions to four over the nationwide unrest.

The toll includes those who have taken to the streets as well as dozens of police, troops and IRGC militia who have died in clashes with demonstrators or who were killed elsewhere.

Iranians have defied such warnings throughout the popular revolt in which women have played a prominent role.

President Ebrahim Raisi appeared to link the two tragedies when he declared that 'the intention of the enemy is to disrupt the country's progress, and then these riots pave the ground for terrorist acts'.

Despite heightened security measures, columns of mourners had poured into Saqez in the western Kurdistan province to pay tribute to Amini at her grave at the end of the traditional mourning period.

A witness in Saqez describes the cemetery where Amini is buried as being filled with members of the volunteer Basij militia and police.

Although the unrest does not appear close to toppling the system, the protests have widened into strikes that have closed shops and businesses, touched the vital energy sector and inspired brazen acts of dissent against Iran's religious rule.

Outrage over Mahsa Amini's death, three days after she was arrested by Iran's notorious morality police, has fuelled the biggest wave of street protests and violence seen in the country for years.

The unrest has underlined pent-up frustrations over freedoms and rights in Iran, with many women joining in.

Protests ignited by the death of Mahsa Amini while in the custody of Iran's morality police have turned into one of the boldest challenges to the clerical leadership since the 1979 revolution.