The United States has acknowledged that Iran would eventually need to be involved in diplomatic discussions on ending the Syrian conflict, Press TV reported.
The US State Department said on Monday that Iran is a stakeholder in this process because of Tehran's close relationship with Syrian President Bashar al-Assad.
"At some point ... we know there's going to need to be a conversation with Iran toward the end of a political transition there," Spokesman John Kirby told reporters in Vienna on Monday.
Kirby made the remarks following talks on Friday in the Austrian capital between US Secretary of State John Kerry and counterparts from Russia, Saudi Arabia and Turkey on a political settlement in Syria.
"They are a stakeholder in this process. They do have a relationship with the Assad regime; they do have a relationship inside Syria," the spokesman added.
Several US officials said Tuesday that Iran has been invited to participate for the first time in international talks over Syria's future.
The US officials, speaking on the condition of anonymity, said Iran has yet to reply.
Kerry and Saudi Arabia's King Salman pledged Friday to further boost the militants operating in Syria while stressing the need for a "transition away" from President Assad.
Before meeting Salman, Kerry accused Assad of standing in the way of peace efforts in Syria.
"One thing stands in the way of being able to rapidly move to implement that, and it's a person called Assad," he said in Vienna.
The United States -- with assistance from its regional allies especially Turkey, Jordan and Saudi Arabia -- has been arming and training militant units to combat the Syrian government.