The father of Mahsa Amini was briefly detained on Saturday, human rights groups said, amid a heavy security force presence on the first anniversary of his daughter's death in Iranian police custody that sparked months of anti-government protests.

Amjad Amini was warned against marking the anniversary of his daughter's death before being released, the Kurdistan Human Rights Network said. Iran's official IRNA news agency denied that Amjad Amini was arrested, but it did not say if he was briefly detained or warned.

Earlier, social media and reports by rights groups spoke of security forces taking up positions around Amini's home in Saqez, in western Iran.

The death of the 22-year-old Kurdish woman in the custody of the morality police last year for allegedly flouting the Islamic Republic's mandatory dress code triggered months of protests that represented the biggest show of opposition to the authorities in years.

Many called for an end to more than four decades of Shi'ite clerical rule.

According to social media posts, Amini's parents had said in a statement earlier this week that, despite government warnings, they would hold a "traditional and religious anniversary ceremony" at their 22-year-old daughter's grave in Saqez.

A massive security force presence was deployed in Iran's mostly Kurdish areas on Saturday in anticipation of unrest, according to human rights groups.