The Turkish army has begun setting up "observation posts" in Syrias northwestern Idlib province in its efforts to create a de-escalation zone, the military said on Friday, although the move was seen partly aimed at containing the Kurdish YPG militia. "On October 12, we began activities to establish observation posts," the military said in a statement. Over 100 soldiers, including special forces, and 30 armored vehicles entered Idlib, Turkeys Hurriyet daily reported on Friday, as it speculated more troops could be sent to the province over the next few days. Idlib is largely controlled by Hayat Tahrir al-Sham (HTS) which has ousted more moderate rebels in recent months. The Turkish army is backing the pro-Ankara Free Syrian Army that will need to oust HTS members in the area to allow Iranian, Russian and Turkish forces implement the de-escalation zone. The move comes after the Turkish army launched a reconnaissance mission on Sunday as part of efforts by Ankara along with Moscow and Tehran, to set up the zone in line with accords in Astana peace talks. They agreed on four such ceasefire zones in Syria as a prelude to negotiations. 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. However, the Turkish deployment is also intended to rein in the Kurdish YPG militia, which holds the Afrin region next to Idlib, a senior rebel official involved in the operation said. "(It is) in line with Astana 6 resolutions to ensure the area is protected from Russian and regime bombing and to foil any attempt by the separatist YPG militias to illegally seize any territory," said Mustafa Sejari, an official in an FSA rebel group. The Britain-based Syrian Observatory for Human Rights confirmed late Thursday that a military convoy of Turkish forces entered Idlib before heading towards the western part of Aleppo province. The fourth de-escalation zone includes Idlib but also parts of the neighboring Latakia, Hama and Aleppo regions.