GLOBAL union IndustriALL has demanded the release of workers detained by Iran’s theocratic regime during May Day protests in front of the country’s parliament.

General secretary Valter Sanches has written to President Hassan Rouhani over the series of arrests, following which many leading trade unionists remain behind bars.

Those who gathered outside the Iranian parliament for the May Day rally protested at “instability in the labour force, low and delayed wages, privatisation … and pressure on independent unions and activists.”

Pensioners, teachers and university students joined the demonstration, chanting: “Workers, teachers, students, unite, unite.”

The protesters also chanted: “With all these embezzlements, workers are in prison,” expressing their anger at government corruption and the detention of workers.

Iranian authorities arrested at least 12 members of the May Day organising committee on April 26, nine of whom were released over the course of the weekend.

Just days later, independent union leaders from the Syndicate of Painters, the Syndicate of Workers of the Tehran and Suburbs Bus Company and the Free Union of Workers in Iran were detained. It is believed that they are still in prison.

Prominent trade unionists including Reza Shahabi, Kayvan Samimi, Hassan Saedi, Vahid Fereydouni and Mohammad Ali Eslaghi were among 30 arrested at the May Day rally after being allegedly beaten by plain-clothes agents.

In his letter, Mr Sanches noted that he leads a union representing more than 50 million workers in more than 140 countries, including Iran.

He urged Mr Rouhani to intervene to guarantee the immediate release of trade union leaders and activists “unlawfully detained on April 26 and 29 and on May Day.

“Workers were calling on your government to implement international core labour standards, which have been ratified by Iran,” he said, demanding that the government abide by its legal obligations.