The Turkish president said the major offensive was the follow-up of the so-called Euphrates Shield Operation in northern Syria, which was launched in August past year without granting any permission from Damascus, in a declared objective of clearing Turkey's southern border of the Takfiri Daesh terrorist group.
"We intend to further enhance our steps in providing safety to Idlib now".
Free Syrian Army fighters had reportedly entered Idlib Friday night, according to earlier media reports, but the Turkish president denied Ankara-backed forces had yet entered.
Turkey said on Thursday that it was prepared to carry out a cross-border operation to retake Syria's northern city of Afrin when necessary.
Idlib is largely held by the Hay'et Tahrir al-Sham alliance, which was not part of the talks and has rejected the implementation of a de-escalation zone. "Salah al-Din al-Shishani is still alive and is somewhere in the regions controlled by militant groups in the west of Aleppo province".
"Russian and Iranian observers will be in some regions here, and we will have our observers inside Idlib".
Ankara's relations with Berlin has been strained since the defeated coup attempt in Turkey past year as Turkish leaders slammed Germany for failing to show strong solidarity with the Turkish government against the attempted military coup.
TRT World's Sara Firth, who is in the southern Turkish province of Hatay on the Mediterranean coast, explains the latest efforts to build a safe zone in northern Syria. Turkish soldiers are expected to join the operation later, he said.
Airstrikes were reported in parts of Idlib on Saturday, follows a month of heavy bombardment of the province by Russian Federation and the Syrian regime killing scores of civilians.
Two waves of air strikes on Idlib killed at least 13 civilians over the past 24 hours, a Britain-based monitoring group said on Saturday.
German Chancellor Angela Merkel came under enormous pressure from her rivals to sharpen tone towards Turkey, particularly due to the arrests of around 10 German citizens, including a reporter and a human rights activist, for alleged support for terrorist organisations.
Idlib and surrounding areas of northwest Syria are among the largest bastions for rebel groups fighting the regime of Bashar al-Assad, but have increasingly fallen under the sway of insurgent factions.