The UN Security Council has rejected a US attempt to extend the 13-year arms embargo on Iran, US Secretary of State Mike Pompeo said on Friday.
Russia and China opposed extending the weapons ban, which is due to expire in October under a 2015 nuclear deal between Iran and world powers which intended to curb Tehran's nuclear ambitions in exchange for sanctions relief.
Eleven members abstained, including France, Germany and Britain, while Washington and the Dominican Republic were the only yes votes.
Mr Pompeo lambasted what he called the Security Council's "failure to act decisively" as "inexcusable".
The vote, he said, "paved the way for the world’s leading state sponsor of terrorism to buy and sell conventional weapons without specific UN restrictions in place for the first time in over a decade".
"The United States will never abandon our friends in the region who expected more from the Security Council," he said, adding that the US would "continue to work to ensure that the theocratic terror regime does not have the freedom to purchase and sell weapons that threaten the heart of Europe, the Middle East and beyond".
China's UN Ambassador Zhang Jun said in a statement after the vote that the result "once again shows that unilateralism receives no support and bullying will fail".
The United States could now follow through on a threat to trigger a return of all UN sanctions on Iran using a provision in the nuclear deal, known as snapback, even though President Donald Trump abandoned the accord in 2018. Diplomats have said the United States could do this as early as next week, but would face a tough, messy battle.
"In the coming days, the United States will follow through on that promise to stop at nothing to extend the arms embargo," US Ambassador to the United Nations Kelly Craft said in a statement.
Diplomats have said such a move would put the fragile nuclear deal further at risk because Iran would lose a major incentive for limiting its nuclear activities. Iran already has breached parts of the nuclear deal in response to the US withdrawal from the pact and unilateral sanctions.
Iran's UN Ambassador Majid Takht Ravanchi warned the United States against trying to trigger a return of sanctions.
"Imposition of any sanctions or restrictions on Iran by the Security Council will be met severely by Iran and our options are not limited. And the United States and any entity which may assist it or acquiesce in its illegal behaviour will bear the full responsibility," he said in a statement.
The US on Tuesday had cut its draft resolution to only four paragraphs to gain more support for the embargo extension. It said it was "essential to the maintenance of international peace and security".
Outgoing US Special Representative Brian Hook had expressed concerns about the arms embargo expiring back in October.
The GCC had backed America in its attempt and called on the UN to extend an international arms embargo on Iran, a move pushed strongly by the US.
The secretariat of the GCC said in a letter to the UN Security Council that Iran's continued interference in neighbouring countries made an extension necessary.
Iran “has continued to proliferate weapons across the region as an integral part of its expansionist regional policy and longstanding interference in the internal affairs of Arab states, including GCC member states, in clear violation of the UN Charter,” the GCC said.
Russia's Putin proposes summit to avoid 'escalation'
Russian President Vladimir Putin on Friday proposed a video summit with the United States and the remaining parties to the nuclear deal - Britain, France, China, Germany and Iran - to try to avoid further "confrontation and escalation" over Iran at the UN.
"The issue is urgent," Mr Putin said in a statement, adding that the alternative was "only further escalation of tensions, increasing risk of conflict - such a scenario must be avoided".
Asked if he would take part, President Trump told reporters, "I hear there's something, but I haven't been told of it yet".
French President Emmanuel Macron is open to taking part in a video summit, the Elysee palace said.
The United States has argued that it can trigger a sanctions snapback because a UN Security Council resolution enshrining the nuclear deal named Washington as a participant. But the remaining parties to the deal are opposed to the move.
Mr Putin said Russia, an ally of Iran in the Syrian civil war, remained fully committed to the nuclear deal and that the aim of a summit would be to outline steps aimed at avoiding "confrontation and escalation of the situation in the Security Council".
Mr Trump has said he wants to negotiate a new deal with Iran that would prevent it from developing nuclear weapons and also curb its activities in the region and elsewhere.
The US President, who has walked away from a series of international agreements, has dubbed the 2015 nuclear deal - reached under his predecessor Barack Obama - "the worst deal ever".