The army drove out the last rebel fighters from the Hama countryside - the latest in a string of crushing blows across Syria - and advanced on a Turkish military post there.
Still, the prospect of more advances in parts of Syria that remain outside his control is obstructed: in the northwest by Turkey's interests near its border, and in the northeast by the presence of USA forces alongside Kurdish fighters.
President Recep Tayyip Erdogan will pay a one-day-visit to Russian Federation on Tuesday, his office said Friday.
Cavusoglu acknowledged that "there are clashes in the Idlib region".
"Regime forces have surrounded the Turkish observation post in Morek after capturing other towns and villages in this pocket", the Observatory said.
Syrian Arab Army (SAA) officials reported the recapturing of the strategic town of Khan Sheikhoun in the southern countryside of Idlib province on Thursday.
The Turkish presidency has also said that it will not abandon any of its observation posts in Syria.
The Syrian army said on Friday that it had seized control of a handful of towns and their environs in south Idlib and northern Hama, including Khan Sheikhoun, Kfar Zita and Morek. That move again drew rebuke from Turkey, with Foreign Minister Mevlut Cavusoglu saying that Turkish troops would not leave the observation post.
"We are there, not because we can't leave but because we don't want to leave", he told reporters, adding that the issue was being discussed with Damascus allies Russian Federation and Iran.
The Turkish troops' mission was to oversee the establishment of a buffer zone agreed by Ankara and Moscow in September.
"The Secretary-General said that he is deeply troubled by the continued escalation in north-west Syria and the prospect of an offensive deeper into Idlib, which could trigger a new wave of human suffering possibly impacting more than 3 million people", Stephane Dujarric, spokesman for Secretary-General Antonio Guterres, told a press conference late Wednesday.
Ankara backs rebel forces that control swathes of territory north of Idlib under its sphere of influence, and some that have a presence in Idlib.
"The president stated the regime's ceasefire violations and attacks in Idlib are causing a big humanitarian crisis, that these attacks are damaging the solution process in Syria and pose a serious threat to our country's national security", it said.
The Idlib region, which sits on the Turkish border, is the last major stronghold of opposition to the Russia-backed Syrian government.
The war in Syria has killed more than 370,000 people since it started with the brutal suppression of anti-government protests in 2011.
Around 900 civilians have been killed, according to the Observatory.