The southwest is of concern to the United States, which past year brokered a "de-escalation" deal with Jordan and President Bashar al-Assad's Russian allies, which has largely contained the war near the frontier with Israel.
With military backing from Russian Federation and Iran, he has reclaimed most of the territory lost to rebels in the wake of the popular uprising that swept the country in 2011 and quickly descended into all-out civil war.
The government had started now opening doors for negotiations with the SDF, who control northern and eastern areas of Syria where United States forces are deployed.
Fighting erupted at the end of April between government forces and SDF fighters in the oil-rich Deir Ezzor province, formerly held by the Islamic State (IS) group, driven out of the overwhelming majority of the region under the blow of multiple offensives. They led rival fronts against Islamic State militants previous year, and they maintain a protracted front against each other along the Euphrates River.
US President Donald Trump and other Western leaders ordered missile strikes in response to an alleged chemical weapons attack in the rebel held enclave of Douma, in Eastern Ghouta.
He added: "The Americans should leave, somehow they're going to leave". Iran, in conjunction with the Lebanese militant group Hezbollah, now operates a network of militias recruiting from across the Mideast to fight on Assad's behalf and maintains a command structure separate from the Syrian government. Trump has already said he hopes to pull USA troops out of Syria within a matter of months after the complete defeat of ISIS in Syria's eastern provinces.
Russian Federation said on Monday only Syrian army troops should be on the country's southern frontier. However, a senior Syrian official has vehemently denied this report.
"Actually, we had tens of Syrian martyrs and wounded soldiers", he said.
The pro-Assad commander, speaking on condition of anonymity, said the Syrian army's preparations for the assault were complete.
Israel, which is deeply alarmed by Tehran's influence in Syria, earlier this month said it destroyed dozens of Iranian military sites in Syria, after Iranian forces fired rockets at Israeli-held territory for the first time.
Russian Defence Minister Sergei Shoigu on Thursday discussed a de-escalation zone in southern Syria with Israeli Defence Minister Avigdor Lieberman when the two met in Moscow, TASS news agency said. Liberman tweeted after the meeting: "The State of Israel appreciates Russia's understanding of our security needs and especially the situation on our northern border".
Israel wants to see a deal that initially forces Iran to withdraw 70 to 80 kilometers from the border and eventually from all of Syria. The agreement envisages Iranian forces pulling out from the entire area and Syrian rebels there surrendering heavy weapons.