Washington, Sept 3, 2019 (AFP) -

The United States on Tuesday imposed sanctions on Iran's space program, saying that a recent explosion on a launch pad was a sign of missile work.

"The United States will not allow Iran to use its space launch program as cover to advance its ballistic missile programs," Secretary of State Mike Pompeo said in a statement.

"Iran's August 29 attempt to launch a space launch vehicle underscores the urgency of the threat," he said.

Pompeo said that the United States was imposing sanctions on the Iran Space Agency as well as two affiliated research centers.

Under the orders, all US citizens or residents would be held criminally responsible for interacting with Iran's space program.

"These designations should serve as a warning to the international scientific community that collaborating with Iran's space program could contribute to Tehran's ability to develop a nuclear weapon delivery system.

President Donald Trump on Friday tweeted a high-resolution picture pointing to damage at a satellite launch pad and said the United States had nothing to do with it.

The tweet gathered wide attention not only for Trump's denial but due to speculation the president was taking to his favorite medium to show US intelligence that was likely classified.

While Trump focused on denying a role by the United States -- which has widely been reported to have used clandestine means to set back Iranian military development -- Pompeo said that the launch showed a threat from Iran.

Iranian government spokesman Ali Rabiei on Monday confirmed an explosion at a satellite launch pad in the north of the country and blamed a technical fault.