But Mr Assad set his sights on regaining full control of the provinces after defeating rebels in the Eastern Ghouta region outside the capital Damascus in April.
The campaign has put more than half the province under the control of President Bashar Al Assad's government, compared with just 30 per cent earlier, according to the Syrian Observatory for Human Rights.
The entire southwest is part of a "de-escalation zone" agreed a year ago by Russian Federation, the United States and Jordan. While in Israel said that they did not intend to intervene in the events in Syria.
More and more Israeli forces surge into the occupied Golan Heights these days, reinforcements dispatched with an eye toward fighting in the war across the frontier in neighboring Syria.
Talks to end the Syrian government's offensive on Deraa province collapsed on Saturday after rebels rejected a demand to surrender by regime ally Russian Federation.
Neighbouring Jordan says it can not afford to take any more refugees and is turning away the internally displaced at the border.
Clashes continued between opposition factions and pro-government forces throughout the day on Monday, with the heaviest fighting concentrated near the town of Nawa in Daraa's western countryside, a rebel commander told Syria Direct on Monday morning.More news: England fans wasted so much beer celebrating Harry Kane's goal vs. Colombia
United Nations High Commissioner for Human Rights Zeid Ra'ad al-Hussein warned of a humanitarian "catastrophe" Friday in the southwestern Syrian city of Daraa if the fighting continues to escalate between Russian-backed Syrian forces and armed rebels.
In 1981, Israel annexed part of Golan in a move unrecognized by the global community, while a smaller part of the area is under Syrian control. So far, the US has remained silent in the face of a breach, and rebels are accusing them of making a "malicious deal" to remain silent.
Shortly after the collapse of negotiations, airstrikes intensified on rebel-held parts of Daraa province that borders Jordan.
The army has already captured large parts of the eastern zone of rebel-held territory in Deraa province less than two weeks into its offensive, however.
Mr Safadi also said he would hold talks with his Russian counterpart in Moscow on Tuesday, which he hoped would "take us more steps forward to contain this crisis and prevent more destruction".
The Observatory said at least 46 civilians, including 15 children, have been killed since the offensive began, including the victims of Thursday's airstrike.