The ceasefire comes as part of the Syrian army's support to the "efforts of national reconciliation", according to the report.
Russia, Turkey and Iran, who back opposing sides in Syria's brutal civil war, have brokered several rounds of peace talks in Astana this year, bringing together the Syrian government and rebel forces.
The office of United Nations special mediator for Syria, Staffan de Mistura, said in a statement that he wants to convene a seventh round of peace talks in July followed by further talks in August and September, Reuters reported. One resolution was introduced by France to end Russian airstrikes in Aleppo, while the other was a Russian-introduced resolution for ceasefire and aid, asserting Egypt's support for "all efforts to end the Syrian conflict", according to a MFA statement.
Deraa is a major front line in the conflict.
The ceasefire may alleviate pressure on pro-Assad forces, thereby allowing the regime to push for more territory on the border of Iraq and Syria.
De Mistura said this week a new round of talks would depend on the progress made in setting up the de-escalation zones.
A Free Syrian Army fighter speaks on radio at al-Nuaimah village in Deraa province, Syria on June 17, 2017.
The SOHR said there was a "cautious calm" by 7pm local time (16:00 GMT) on Saturday.
The diplomat added that the officials were exchanging viewpoints on the boundaries of a ceasefire line between the foreign-backed extremists and Syrian army soldiers, which is projected to yield a comprehensive agreement and outline the control of border crossings with Jordan.
"The regimes forces have stopped their military operations after big losses in equipment and men since the start of their campaign over a month ago ... after the failure of repeated attempts to advance", Rayess said.