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 Syrian state television.
The army general command said the ceasefire took effect from midday on Sunday and was being done to support "reconciliation efforts", in the second unilateral ceasefire in the last two weeks.
A spokesman for the Southern Front, a coalition of Free Syrian Army rebel groups, cast doubt on whether the Syrian army and its Iranian-backed allies would halt attacks on the front lines in Deraa and in Quneitra province.
"The Free Syrian Army are very distrustful of the regime's intentions in abiding by the ceasefire. It will be like the previous one," Major Issam al Rayes told Reuters.
On June 17, the army announced a ceasefire that only affected fighting in the southern city of Deraa along the border with Israel.
The latest announcement extends the ceasefire from Deraa to the whole of southern Syria, including the southwestern Quneitra province near the border with Israel and Sweida province in the southeast.
Rebels launched an offensive last week against government-held Baath, the provincial capital of the Syrian Golan Heights. They made initial gains on the southern and western fringes of the city, but an army counterattack mostly pushed the rebels back to their former positions.
The Israeli army has also struck several times at Syrian army outposts in the area, where the Iranian-backed Hezbollah has a strong presence, saying it was retaliating for errant fire from Syria's positions there.
Speaking at Israel's northern border on Monday, Defense Minister Avigdor Lieberman said that while Israel does not want to enter Syria's war, it will "not tolerate any violation of Israeli sovereignty."
Commenting on fighting taking place in the border region, Lieberman said: "The fighting and events in the new Quneitra area do not concern us, we are not looking for excuses, not to take part in the civil war and not to take sides."
"If anyone is planning to violate our sovereignty, it would not be in his favor, we will be extremely upset and I do not recommend testing us," he said.
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