Iran executed four individuals arrested last year for “collaborating with Israel” and allegedly involved in acts of sabotage, the Judiciary announced on Friday.

Iran International reported on Thursday that these prisoners had been moved to solitary confinement, which usually signals impending execution for those on death row.

The Judiciary said Aran Omri, Rahman Parhazou, Vafa Hanareh, and Nasim Namazi were executed, while a fifth death row prisoner, Mansour Rasouli, who was also expected to be executed, was not mentioned.

The relocation of the individuals to solitary confinement occurred shortly after the reported killing of Razi Mousavi, a senior Revolutionary Guards commander, in an attack attributed to Israel in the Zainabiyya neighborhood of Damascus, Syria.

Some observers interpret the executions as potential retaliation by the Islamic Republic for the killing of Razi Mousavi. Mousavi played a crucial role in logistics and support for the Quds Force of the Revolutionary Guards, being one of the six senior commanders instrumental in the survival of Bashar al-Assad's regime and the consolidation of Hezbollah in Lebanon.

Families of the prisoners gathered outside the prison in Urmia, northwest Iran, Thursday night to demand a stay of execution.

The accused were tried in secrecy and except a brief announcement about their alleged crimes, no other details were released. Human rights monitoring groups say that the convicted prisoners had appealed their death sentence, but authorities ignored the legal process and carried out the death sentences.