"The Secretary-General is gravely concerned by the recent military escalation, including ground offensives and aerial bombardments, in southwestern Syria," Stephane Dujarric said in a statement.
"The Secretary-General is also concerned at the significant risks these offensives pose to regional security," his spokesman said. "He calls for an immediate end to the current military escalation and urges all stakeholders to respect their obligations."
Moreover, Antonio Guterres also called for an instant end to the military escalation in the embattled region.
US State Department spokeswoman Heather Nauert issued a statement on Thursday citing reports of an offensive by the Syrian government in the southwest and warning against incursions into the Daraa, Quneitra and Suwayda ceasefire zones, agreed by the United States, Russia and Jordan.