Chaab had been held in Iran since October 2020 after he vanished during a visit to Turkey before going on trial in Tehran, which does not recognise dual nationality.
Convicted of “corruption on earth” for heading a rebel group, he was condemned to death in December and Iran’s supreme court upheld the sentence in March.
“The death sentence for Habib Chaab… nicknamed Habib Asyud, the head of the Harakat al-Nidal terrorist group… was carried out today, Saturday morning,” the judiciary’s Mizan Online website reported. “He was hanged.”
Swedish Foreign Minister Tobias Billstrom, whose country currently holds the European Union’s rotating presidency, denounced the execution as “inhuman”.
“The death penalty is an inhuman and irreversible punishment and Sweden, together with the rest of the EU, condemns its application in all circumstances,” Billstrom wrote on Twitter.
He added that Stockholm had contacted Tehran “and demanded that the sentence not be carried out”.
Chaab had been accused of staging attacks since 2005 “under the protection of… the Mossad and Sapo” — the Israeli and Swedish spy agencies, respectively.
Prosecutors in Iran allege other leaders of Harakat al-Nidal are based in Denmark, the Netherlands and Sweden, with the group receiving financial and logistical support from Saudi Arabia.
Iranian state television had aired a video of Chaab in which he claimed responsibility for a 2018 attack on a military parade in Ahvaz, the capital of the southwestern province of Khuzestan, that authorities said killed 25 people and wounded almost 250.
In the footage, Chaab admitted to working with Saudi intelligence services. Such confessions are frequently condemned by rights groups based outside of Iran as “forced”, arguing they are often obtained under duress.
The Oslo-based Iran Human Rights group also denounced Chaab’s reported execution, saying he had been “subjected to torture following his abduction” and calling for a “strong response by the international community to this extrajudicial killing”.
Harakat al-Nidal, or Arab Struggle Movement for the Liberation of Ahvaz, is considered by Iran as a “terrorist group” and blamed for orchestrating attacks in Khuzestan.
The oil-rich province is home to a large Arab minority, and its people have long complained of marginalisation.
Six other members of Harakat al-Nidal were sentenced to death in March over attacks carried out by “orders of their European leaders”, Mizan Online has said.
In December 2020, the Turkish authorities announced the arrest of 11 people suspected of having kidnapped Chaab in Istanbul before taking him to Van, a city near Turkey’s eastern border with Iran, and handing him over to the authorities in Tehran.
Iran executes more people yearly than any other nation except China, according to rights groups including Amnesty International, with those sentenced to death hanged.