The army general command said the ceasefire took effect from midday (0900 GMT) on Sunday and was being done to support "reconciliation efforts", in the second unilateral ceasefire in the last two weeks.
On June 17, the army announced a ceasefire that only affected fighting in the southern city of Deraa along the border with Israel.
This latest announcement extends the ceasefire alongside Deraa city to the whole of southern Syria, including the strategic southwestern Quneitra province near the border with Israel and also Sweida province in the southeast.
Syrian regime soldiers stands guard in Syria's southwestern Quneitra province on July 2, 2017 during ongoing clashes for control of the city of al-Baath
The Syrian army said it would suspend combat operations in southern Syria until Thursday, including in Quneitra province where Israel has hit army outposts in recent days, according to a statement carried by state television.
