Iran expressed to Turkey on Monday its opposition to an incursion into northern Syria.
In a telephone call to his Turkish counterpart, Iranian Foreign Minister Mohammad Javad Zarif urged Turkey to respect Syria's integrity and sovereignty.
“(Mohammad Javad) Zarif, opposed military action and emphasized respect for Syria’s territorial integrity and national sovereignty and the need to fight terrorism and bring stability and security to Syria,” state broadcaster IRIB said, about the phone call with Mevlut Cavusoglu.
US President Donald Trump this week declared that US troops will step aside for an expected Turkish attack on Syrian Kurdish factions, longtime US allies against the ISIS group.
Iran, Turkey and Russia have been working together as part of the so-called Astana group on the Syrian war, talks that have run parallel to UN efforts to find a solution to the conflict.
Russia said on Tuesday it was not informed in advance by the United States or by Turkey about any agreements they had reached about plans to withdraw US troops from northeastern Syria.
Kremlin spokesman Dmitry Peskov told reporters it remained to be seen how many US troops would be withdrawn, and that other details about the plans remained unclear.
"We are very closely watching the situation," he said.