WASHINGTON (Reuters) - The United States imposed sanctions on Iran’s civilian space agency and two research organizations on Tuesday, saying they were being used to advance Tehran’s ballistic missile program.

The U.S. Treasury sanctions targeted the Iran Space Agency, Iran Space Research Center and the Astronautics Research Institute, according to a statement on its website.

“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.

He said Iran’s Aug. 29 attempt to test a space launch vehicle underscored “the urgency of the threat.”

An Iranian rocket exploded on its launch pad at Imam Khomeini Space Center in northern Iran before its scheduled launch last Thursday. The explosion followed Iran’s failed attempt to launch a satellite in January.

The sanctions, part of a years-long U.S. pressure campaign to keep Iran from developing nuclear weapons, are the first imposed on Iran’s space agencies, according to the State Department. The United States fears long-range ballistic technology used to put satellites into orbit could also be used to launch nuclear warheads.

The Iran Space Agency develops satellites and launch vehicle technology, and works with the Iran Space Research Center on day-to-day tasks as well as research and development, according to the State Department. The two have also worked with a sanctioned liquid propellant ballistic missile organization, Shahid Hemmat Industrial Group, the State Department said.

The Astronautics Research Institute has managed the space vehicle launch project, according to the department.

Tehran denies its space activity is a cover for developing weapon launches.

On Friday, U.S. President Donald Trump posted on Twitter a photo of what appeared to be the site of the failed Iranian satellite launch.

“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,” Pompeo said.

Trump withdrew from a 2015 multi-national nuclear deal with Iran, saying it did not go far enough.