The much-anticipated peace talks on Syria - set to begin in Switzerland this week - could fall apart before they even get off the ground after the United States said Iran shouldn't attend the talks.
Washington's UN envoy Samantha Power says Iran is not entitled to take part because it had not explicitly and publicly backed a transition process away from the Bashar al-Assad regime.
Syria's main opposition group also say it will not participate in the talks, unless Iran, the strong backer of Assad regime, is disinvited, and Tehran pulls out its military presence out of Syria.
The peace talks are scheduled to begin on Wednesday in Montreux, Switzerland.
More than one-hundred-thousand people have been killed and millions more displaced since the outbreak of the Syria conflict some three years ago.