Washington, September 20 (RHC)-- The United States has broken with all other permanent members of the United Nations Security Council and unilaterally declared the re-imposition of all UN sanctions against Iran -- a claim rejected by Iran and the international community, including Washington's close allies, as having no legal basis.

In a statement on Sunday following the expiration of a deadline set by Washington, Secretary of State Mike Pompeo threatened "consequences" for any UN member state that does not comply with the punitive measures, which were lifted under a landmark nuclear deal that was signed between six world powers and Iran in 2015 but was abandoned by the US more than two years ago.

In addition to adhering to a conventional arms embargo that is due to expire next month, Pompeo said member states must comply with restrictions such as the ban on Iran engaging in nuclear enrichment and reprocessing-related activities; the prohibition on ballistic missile testing and development; and sanctions on transfer of nuclear and missile-related technologies.

"If UN Member States fail to fulfil their obligations to implement these sanctions, the United States is prepared to use our domestic authorities to impose consequences for those failures and ensure that Iran does not reap the benefits of UN-prohibited activity," Pompeo said.

His statement came a month after the U.S. officially triggered the process aimed at restoring all UN sanctions on Iran, claiming significant Iranian violations of the Joint Comprehensive Plan for Action (JCPOA), the formal name for the 2015 deal that was endorsed by the Security Council.

Despite pulling out of the deal in May 2018 and reimposing crippling sanctions on Iran, Washington argues it is still technically a "participant" and could trigger the so-called "snapback".  This was a mechanism devised by the U.S. negotiating team before the signing of the JCPOA that stipulated that if Iran breached its commitments, all international sanctions could snap back into place.