According to the Tasnim news agency, Zarif said, “We are hostile to their presence and we have not invited them.” This goes against the position of the other two organizers of the talks — Russia and Turkey — which have said the new US administration of Donald Trump should be represented in Astana on Monday.

This will be the first time, since the conflict began in 2011, that the US has not been at the centre of peace negotiations.

Iran’s foreign ministry spokesman Bahram Ghasemi told the media on Wednesday, “At this stage, we must keep the tripartite set-up. Any enlargement could increase the risk of failure. Our policy is to not add other countries at this stage.”

This was concurred in by article in The Washington Post by Liz Sly, on January 17, who wrote,  “Iran opposes the participation of the United States in Syrian peace talks backed by Russia that are due to be launched in Kazakhstan next week, Iranian Foreign Minister Mohammad Javad Zarif said Tuesday.”

This statement contradicts Russia’s and Turkey’s promises, as well as indications from U.S. officials that the  Trump administration would be invited to the January 23 talks, scheduled in the Kazakhstan capital, Astana.

The potential for conflict over at least one of the Middle East’s flashpoints between Tehran and the incoming Trump administration is highlighted by these comments, as the new administration indicated that it plans to adopt a more hawkish posture toward Iran than President Obama’s administration.

“We have not invited the U.S. and oppose their presence” Zarif said, according to Iran’s Press TV. It is not immediately clear whether Iran will refuse to attend, if the United States were invited. The talks are part of a three-way process led by Russia and including Turkey and Iran, who now the three most powerful players in Syria. The talks are aimed at forging a settlement in Syria after the failure of the Obama administration’s diplomacy.

Russian Foreign Minister Sergei Lavrov told reporters in Moscow, that the opening round will include representatives of Syrian rebels, meeting with members of the Syrian government to discuss the fragile cease-fire that went into effect on December 29.  Representatives of the other invited countries will attend in the role of observers, rather than participants.

If this meeting takes place, it will represent a profound moment for the Syrian conflict, as the military protagonists will be brought together for the first time since the uprising against President Bashar al-Assad in 2011.

It could also be a significant moment for the wider Middle East, signaling the first major initiative to resolve a regional conflict in which the United States is not playing a leading role.  This is a Russian-led process, diplomats said, and Turkey and Iran are partnering with Russia in the effort.

Invitations have not yet been formally issued, partly because Turkish efforts to persuade the Syrian rebels to attend have gone on longer than expected.  Rebel commanders confirmed on Tuesday, that half a dozen mostly Turkish-backed groups, most of them based in the north of the country, will send representatives.

One of the three sponsors of the peace talks, Iran has not signed the agreement reached between Russia and Turkey that launched the cease-fire. This suggests that Tehran has reservations about an effort that may erode its influence in Syria.

Russian President Vladi¬mir Putin and President-elect Donald Trump and have said that they regard Syria as one of the areas in which the United States and Russia could cooperate more closely. Trump stated on several occasions that he hopes better relations with Moscow will help counterbalance Iran’s expanding regional role.

Iran was instrumental in providing the manpower and resources that have helped Assad’s government hold the rebels at bay. 

Sly writes that, “Thousands of Iranian-trained Shiite militia fighters from Iraq and Afghanistan are on the front lines, the Iranian-backed Lebanese Shiite militia Hezbollah is at the forefront of most of the major battles, and Iranian military advisers and commanders are embedded with them in many locations around the country.”

These military conquests strengthened Iran’s role as a dominant player in Syria, and make Iran’s cooperation essential to any peace deal.