US Secretary of State Mike Pompeo on Wednesday urged the UN Security Council to renew the arms embargo on Tehran as China and Iran explore a strategic pact.
Mr Pompeo said a 25-year strategic partnership that is being negotiated between Iran and China was not the first of its kind.
He said that potential security and military aspects of such an agreement meant that extending the UN arms embargo on Iran, which was due to expire on October 18, took on greater urgency.
“China will sell weapons systems to Iran,” if the embargo is not renewed and the pact goes through, Mr Pompeo said.
The deal being negotiated between the two US rivals involved $400 billion (Dh1.46 trillion) in Chinese investments in Iran, including security and intelligence, Iranian officials said this week.
Mr Pompeo is expected to discuss the embargo extension on a trip to the UK and Europe next week.
He said Washington was not far away from presenting a resolution to the Security Council seeking to extend the arms embargo on Iran for another five years.
Mr Pompeo said that Europe was in favour of an extension.
On Wednesday, German Chancellor Angela Merkel discussed the Iran embargo in a call with Russian President Vladimir Putin, said her spokesman, Steffen Seibert.
Russia has voiced its objection to renewing the embargo.
Mr Pompeo is describing the extension of the embargo as a national security issue and said failing to commit to it would spark instability in the Middle East.
“Iran will hold a sword of Damocles over the economic stability of the Middle East, endangering nations like Russia and China that rely on stable energy prices,” he told the UN this month.
But if the Security Council fails to act, the US is not closing the door on other options.
“The United States’ overwhelming preference is to work with this council to extend the arms embargo, to protect human life, to protect our national security and to protect yours,” Mr Pompeo said.
One option would be to reimpose multilateral sanctions if the embargo were not renewed.
But that would require the Trump administration to return to the Iran nuclear deal, under which those sanctions are permitted, from which it withdrew in 2018.
Such a move would all but guarantee that the agreement collapsed.
During his briefing, Mr Pompeo also remembered the victims of the terrorist attacks on a Jewish community centre in Argentina in 1994, and a 2012 attack in Bulgaria on Israeli tourists.
On the anniversary of those attacks, he blamed the Iran-backed group Hezbollah of carrying them out.
Mr Pompeo is due to leave for the UK on Monday and will visit Denmark and other European capitals.