"US Space Command is aware of the Iranian rocket launch failure which occurred early June 12th," said Pentagon spokesperson Uriah Orland.

No explanation was offered for why the launch failed and Iran rejected the original report of it by CNN, saying its satellites remain on the ground.

"The two satellites of the ministry of telecommunications (Nahid and Pars) are at the space organisation," Iran's telecoms minister Mohammad Javad Azari Jahromi said, according to the state news agency IRNA.

"I saw in the news this morning that they were launched 10 days ago," he said.

CNN cited experts at the Middlebury Institute of International Studies in Monterey, California as saying that satellite images of the Imam Khomeini Spaceport in Semnan suggested a new launch attempt would be made in the near future.

Images from June 19 and 20 by Planet Labs show fuel tanks and support vehicles appearing to ready for a launch, the Middlebury experts told CNN.

Orland said Iran's last space launch took place in April 2020, placing a microsatellite, NOUR-1, into orbit.

But from the beginning, US officials said that satellite appeared to have problems.

"However, our persistent observations of this object demonstrate it is uncontrolled and not operational," Orland said.