TEHRAN — An eerie silence filled the air as a crowd of around 300 gathered Sunday just before sunrise in a Tehran park. They awaited the arrival of two young men who were about to die.

The condemned stood shoulder to shoulder, motionless, in front of two police trucks with two nooses hanging from extendable cranes, about 15 feet high. Black-clad executioners were inspecting the remote controls they would use to hang the men, both in their early 20s, who were convicted of stabbing a man in November and stealing his bag and the equivalent of $20.

From behind a makeshift barrier of scaffolding, the crowd jostled for position. “Let’s move to the other side,” one spectator whispered to his wife, pointing to the spot where Iranian state television cameras had been set up. “I think we will have a better view from there.”

Although every year hundreds of convicts are hanged in Iran, a public hanging in a central park in Tehran is a rare event. Most hangings take place inside prisons, according to Iranian judicial officials and international human rights organizations.