"The EU urges the Iranian authorities to refrain from applying the death penalty and carrying out future executions," EU foreign policy chief Josep Borrell's office said a statement .

The three men Majid Kazemi, Saleh Mirhashemi and Saeed Yaghoubi, were hanged after an Iranian court convicted them on charges of killing security force members at a demonstration in the city of Isfahan in November.

Nazanin Boniadi, a British actor and activist of Iranian origin, tweeted that the three men had been executed "after forced confessions and sham trials".

Iranian authorities brutally cracked down on protests that sprang up after the September 16 death in custody of Amini, a 22-year-old Iranian Kurd who was arrested in Tehran for allegedly breaching the Islamic republic's strict dress rules for women.

Amnesty International and other rights groups have documented torture of arrested protesters.

The EU statement emphasised that Iranian officials must observe "due process rights" of detained individuals and ensure they are not subjected to "any form of mistreatment".

It also called on them to abide by "their obligations under international law," including respecting "the rights to freedom of expression and peaceful assembly".

Friday's executions bring to seven the number of Iranians executed in connection with the demonstrations.