According to a report, the soldiers detained the two when they tried to reclaim film footage confiscated from the scene of the blast.
A senior executive from the state IRIB network said US troops had snatched the film from an Iranian cameraman at the scene.
"When the head of the IRIB bureau in Baghdad went to reclaim the film, he was arrested along with a technical operator," he told state television.
Shortly afterwards, television news announced the men had been released.
A report on state television said the two detained included the Baghdad bureau chief of the Islamic Republic of Iran Broadcasting (IRIB), Gholamreza Kouchak.
It was the second time Iranian journalists working for the state network had been detained by US forces.
Troops arrested IRIB director Said Abu Talib and cameraman Suhail Karimi on 1 July for filming at a checkpoint in Iraq, saying their behaviour was suspicious. The men were held for four months.