"No one can say to us, "why are you doing this"?" he thundered. Reconnaissance units have been operating in the area since last Sunday. Turkey's operation is mainly aimed at clearing out HTS and implementing a de-escalation zone in the province.
Sejari, the rebel official, said it was important to contain the YPG to prevent any new military offensive to reach the Mediterranean, something that would require it to capture swathes of mountains held by rebels and Syria's army.
At the weekend, reconnaissance teams entered Idlib province as part of an global agreement to establish four de-escalation zones across Syria.
Three zones are already in place - in Eastern Ghouta near Damascus, in central Homs, and in parts of southern Syria - which are being monitored by Russian military police.
Turkey has supported rebels fighting Syrian President Bashar al-Assad throughout the war. Russia, Syria and Turkey have been discussing a deal for the Turkish involvement.
A large column of Turkish tanks and armoured vehicles has crossed into northern Syria in an operation described as a peacekeeping effort by Ankara but criticised by the Assad regime as a land grab.
Moustafa Sejari, a senior official in rebel group Liwa Al Moutassem taking part in the operation, said on Twitter that the Turkish deployment was meant to "protect the region from bombing and to cut the path of (Kurdish) separatists".
However, the deployment is also meant to rein in the Kurdish YPG militia, which holds the adjacent Afrin region, a senior rebel official involved in the operation said.
"Turkey is not after anything in Idlib but (an) Afrin siege could ignite fire of another war in the region", the YPG said on Twitter.