ANKARA, Feb. 5 (Xinhua) -- Turkish army has started to construct the fourth observation point in the northern Syrian province of Idlib Monday, the Turkish General Staff said in a statement.

"As part of agreements on de-escalation zones reached in Astana, Turkish troops have started to construct the fourth observation point in Idlib," the statement read.

The reconnaissance work for another two observation points has also begun, it added.

Three guarantor countries, Turkey, Iran and Russia agreed in peace talks in Astana to establish de-escalation zones in Idlib, Syria and parts of the Aleppo, Latakia, and Hama provinces.

Under the Astana agreement, Turkey planed to establish 12 observation points, from Idlib's north to south.