The deal marks a new level of involvement for the Trump administration in trying to resolve Syria's civil war.
Although details about the agreement and how it will be implemented weren't immediately available, the cease-fire is set to take effect Sunday at noon Damascus time, said the officials, who weren't authorised to discuss the cease-fire publicly and spoke on condition of anonymity.
Jordan and Israel also are part of the agreement, one of the officials said. The two US allies both share a border with the southern part of Syria and have been concerned about violence from Syria's civil war spilling over the border.
Previous cease-fires in Syria have collapsed or failed to reduce violence for long, and it was unclear whether this deal would be any better.
More From This Section
Earlier in the week, Syria's military had said it was halting combat operations in the south of Syria for four days, in advance of a new round of Russian-sponsored talks in Astana. That move covered southern provinces of Daraa, Quneitra and Sweida. Syria's government briefly extended that unilateral cease-fire, which is now set to expire Saturday - a day before the US and Russian deal would take effect.
Implications for Syria aside, the deal marks the biggest diplomatic achievement for the US and Russia since Trump took office. Trump's administration has approached the notoriously strained relationship by trying to identify a few limited issues on which the countries could make progress, thereby building trust for a broader repair of ties.