Monitoring group says at least 384,000 people have been killed, including more than 116,000 civilians.
Forces will establish a security corridor on either side of the M4 highway.
The agreement raised hopes of an end to one of the bloodiest phases in the nine-year conflict between Russia and Turkey.
Those displaced by the fighting express skepticism over the deal.
Erdogan told reporters the truce would come into effect at midnight on Thursday.
Turkey already hosts nearly four million refugees, most of them Syrians.
Tensions in Idlib rose following the Syrian strike that killed the 33 Turkish soldiers.
Turkish leader sees Syrian ceasefire deal.
Ankara has ramped up its attacks, including drone strikes, against the Russian-backed Syrian forces since Thursday.
Iran says innocent people in Idlib should be protected.
“Significant numbers of migrants and refugees have gathered in large groups at the Greece-Turkey land border," says PM.
“Pakistan expresses its deep concern at the recent developments in Syria’s Idlib region," says FO.
United Nations calls for an immediate ceasefire, Nato holds emergency talks.
The air strike by Syrian forces marks the largest death toll for Turkey in a single day since in Syria in 2016.
Syrian warplanes also launched renewed air strikes on Thursday on residential areas of Idlib city.
Syrian President Assad’s forces are trying to retake the last large rebel-held region in Syria.
"We will come together on March 5 and discuss these issues," Erdogan says.
At least 15 Turkish soldiers have been killed in Syria this month.
UN envoy to Syria warns that the war-torn country is facing "an imminent danger of further escalation".
One day, she will know this is a sound of death but by then, she will have understood what our story is, says Mohammed.
Turkey and Russia support rival groups in the Syrian conflict.
Turkey has 12 observation posts in Idlib as part of the 2018 Ankara-Moscow agreement made in southern city of Sochi.
Erdogan says Ankara will not allow insurgents in Idlib to give them an excuse to attack.
Monday’s incident comes a week after earlier regime shelling killed eight Turkish soldiers.
The advance on Saraqeb comes shortly after Turkey sent additional troops into the region.
Israel has pledged to prevent its main enemy from entrenching itself militarily in Syria.
Russian air strikes also kill 14 civilians in the same area.
Eight of those killed died in a regime barrel bomb attack in the town of Sarmeen, seven from the same family.
Aleppo city has been under full Syrian government control since 2016.
Michelle Bachelet calls for an immediate cessation of hostilities in Idlib.