U.S. and Saudi officials say an expiring United Nations arms embargo on Iran must remain in place to prevent Tehran from acquiring and proliferating weapons across the Middle East.

Speaking at a press conference in Riyadh on June 29 with the Saudi minister of state for foreign affairs, Adel al-Jubeir, the U.S. special representative to Iran, Brian Hook, said lifting the ban would "only embolden" Tehran to spread greater instability and trigger a regional arms race.

"This is not an outcome that the UN Security Council can accept. The council's mandate is clear: to maintain international peace and security," Hook added amid a display of weapons, including drones and missiles, that the two countries say Iran provided to Yemen's Huthi rebels to carry out attacks on Saudi cities.

A UN arms embargo prohibiting Iran from buying or selling conventional weapons is set to expire in October under the terms of a 2015 nuclear deal between Tehran and world powers.

The United States, which withdrew from the nuclear accord in 2018 and reimposed crushing sanctions on Iran, is seeking to gather international support for extending the arms embargo.

China and Russia, both signatories to the nuclear deal believed to be eager to sell arms to Iran, are likely to exercise their veto at the UN Security Council to oppose extending the embargo.

If the arms embargo is lifted, Iran would likely seek to purchase fighter jets, tanks, naval assets, and other weapons from China and Russia to rebuild its aging military hardware.

Faced with the UN arms embargo, Iran has long sought to develop ballistic missiles as a deterrent and employed a relatively inexpensive strategy of asymmetric warfare and use of proxy forces.

"Despite the embargo, Iran seeks to provide weapons to terrorist groups, so what will happen if the embargo is lifted? Iran will become more ferocious and aggressive," al-Jubeir said at the press conference.

"We urge the international community to extend the embargo on selling arms to Iran and on Iran's ability to sell arms to the world," Jubeir said.

The UN arms embargo has not prevented Iran from supplying weapons to allies across the Middle East, including to Syria, Iraqi militias, Lebanon’s Hizballah militant group, and Yemen’s Huthi rebels.

Saudi Arabia has led an Arab coalition fighting the Iran-backed Huthis for more than five years. The multisided civil war in Yemen has led to one of the world’s worst humanitarian disasters.

The United States and Saudi Arabia accuse Iran of providing weapons, including ballistic missiles and drone parts, to Huthi forces to launch cross-border attacks on the kingdom.

The Huthis have carried out multiple ballistic missile and drone attacks on Saudi Arabia, including one last week on the capital, Riyadh, and two cities near the border with Yemen. Saudi Arabia said it shot down the ballistic missiles and drones, which the Huthis claimed targeted the defense ministry and a military base.

In early June, the UN said in a report that cruise missiles used in attacks on oil facilities and an airport in Saudi Arabia last year were of "Iranian origin."

Previous UN reports have found that Huthi rebels received smuggled weapons with similar characteristics to those in Iran in potential violation of the UN arms embargo.

With reporting by AP and Reuters