The top Iranian diplomat has said that Idlib in northwestern Syria must be cleansed of terrorists and returned to the government fold as he arrived in Damascus for key talks.
"Terrorists operating in the remaining parts of Idlib must be cleansed, and the region be returned to the people of Syria," Zarif told reporters on Monday upon arrival in the Syrian capital.
Zarif said on Monday, "Syria's territorial integrity must be preserved, all ethnic groups must collectively start the reconstruction process, and the displaced must return to their families."
The Iranian foreign minister was due to meet Syrian President Bashar al-Assad, Prime Minister Imad Khamis, and his counterpart Walid al-Muallem.
As Syrian President Bashar al-Assad attempts to turn military success into postwar reconstruction, foreign-backed terrorists in Idlib remain the last major hurdle to the program.
The Syrian army gears up for a major offensive to retake the last terrorist stronghold, but it is facing threats of being hit by the US and its allies if a chemical attack takes place in the province.
Russia and Syria say staging a false flag chemical attack has been in the works for some time by militants and British "special forces" in order to give the US a pretext to hit the government.
Russian Foreign Minister Sergei Lavrov said on Monday that the situation in Idlib Province could not be tolerated indefinitely.
Speaking in Moscow, the top diplomat said the Syrian government had every right to wipe out militants in Idlib, Interfax news agency reported.
Lavrov had earlier called the Idlib-based terrorists as an "abscess" which needs to be taken out before harming thousands of civilians who live there.
Lavrov said last Wednesday that terrorists holed up in the city were using ordinary people as human shields.
"So, from all standpoints, this abscess has to be liquidated," the Russian foreign minister said.
For months, Syria has been planning the decisive operation in Idlib, the last of its provinces that still remain under the control of militants.
Presidents of Iran, Russia and Turkey are due to meet in Iran for a third summit on Syria on September 7. On Wednesday, Zarif made a previously unannounced visit to Ankara and held "fruitful" talks with President Recep Tayyip Erdogan.
Turkish Foreign Minister Mevlut Cavusoglu, who attended the meeting, said bilateral ties and Syria were on the agenda.