US President Donald Trump takes his campaign to isolate Iran to the United Nations Security Council on Wednesday, chairing for the first time a meeting that will lay bare divisions between Washington and key allies.
Trump will be wielding the gavel at the top UN body, where the United States this month holds the agenda-setting presidency of the 15-nation council that deals with the world's most pressing security threats.
Trump's appearance in the formal setting of the Security Council chamber could trigger surprises. UN diplomats note that the US president has been known to stray from protocol and procedure.
During his address to the General Assembly on Tuesday, Trump assailed Iran's leaders, accusing them of sowing "chaos, death and destruction" and calling on world governments to isolate Tehran.
Iranian President Hassan Rouhani shot back in his speech, denouncing leaders who have "xenophobic tendencies resembling a Nazi disposition" and slamming the planned council meeting as a "preposterous and abnormal act."
The meeting will show a rift between the United States and its European allies over the Iran nuclear deal that Trump ditched in May after repeatedly dismissing it as disastrous.
The United States has moved to reimpose sanctions that had been lifted under the landmark deal to curb Iran's nuclear program and has vowed to punish foreign firms that do business with Iran.
On Monday, the five remaining parties to the agreement -- Britain, China, France, Germany and Russia -- defiantly announced that they would set up a special payment system to continue trade and business ties with Iran.
The United States had initially said the meeting chaired by Trump would focus on Iran, but later broadened the agenda under the theme of nuclear non-proliferation and weapons of mass destruction.
That opens the door to remarks on chemical weapons use in Syria, the drive to denuclearize North Korea and the nerve agent attack in Salisbury, where the United States and the Europeans can show unity.
The usual practice is for the chair to speak last at council meetings, but in this instance Trump will be the first to address the chamber followed by other heads of state.
One of those will be leftist leader Evo Morales of Bolivia, a non-permanent council member critical of US foreign policy and a close supporter of Venezuela.
After the United States imposed sanctions on Venezuela in May, Morales took aim at Trump, saying he "must understand that the world is not his estate."
French President Emmanuel Macron will address the council meeting as will British Prime Minister Theresa May. Russia and China will be represented by their foreign ministers Sergei Lavrov and Wang Yi.
Iran has not requested to speak at the council meeting, diplomats confirmed Tuesday although Rouhani will hold a press conference soon after it is due to end.
It will be only the third time in UN history that a US president will chair a Security Council meeting. Barack Obama presided over two meetings in 2009 and 2014.
Trump is one of around 130 world leaders attending the General Assembly in New York which formally began on Tuesday.
Speakers scheduled to address the second day of the assembly include the leaders of war-torn Yemen and Afghanistan while Prime Minister Theresa May will make her last speech at the world's foremost diplomatic stage before Britain leaves the European Union.