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 sanctions targeted the Iran Space Agency, Iran Space Research Center and the Astronautics Research Institute, according to a statement on the Treasury Department's 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."

A rocket exploded on its launch pad at Imam Khomeini Space Canter in northern Iran before its scheduled launch last week. 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 U.S. 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 Centre 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.

Washington has warned Iran against rocket launches, fearing the technology used to put satellites in orbit could help it develop the ballistic missile capability needed to launch nuclear warheads. Tehran denies its activity is a cover for such development.

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

The United States of America was not involved in the catastrophic accident during final launch preparations for the Safir SLV Launch at Semnan Launch Site One in Iran. I wish Iran best wishes and good luck in determining what happened at Site One. <a href="https://t.co/z0iDj2L0Y3">pic.twitter.com/z0iDj2L0Y3</a> —@realDonaldTrump

"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.

Meanwhile, Iran's foreign minister said on Tuesday Tehran would further cut its commitments under a 2015 nuclear deal unless European states acted to salvage the pact by Thursday, but that this did not mean the "end of talks," Iranian news agencies reported.

Mohammad Javad Zarif said President Hassan Rouhani would soon announce details of the cuts, according to the semi-official news ISNA. "Implementation of this step does not mean the end of talks," he added.

France has proposed offering Iran about $15 billion in credit lines until year-end if Tehran comes fully back into compliance with the deal, a move that hinges on Washington not blocking it, Western and Iranian sources said.