Rebels in southern Syria said on Friday they were close to reaching a deal with regime ally Russia including a ceasefire and the handover of some territory.
A meeting between rebel and Russian negotiators was still continuing on Friday afternoon with no confirmation of a final agreement.
But its broad outlines were described to AFP by two spokesmen for the joint opposition command in the south.
Hussein Abazeed said a ceasefire would take hold in the southern province of Daraa, known as the "cradle" of Syria's uprising.
"Rebels will hand over their heavy-duty weapons in stages in exchange for the regime withdrawing from four towns" it had recently recaptured, said Abazeed.
Government forces would then take control of a key route running along the border with Jordan, up to the Nassib border crossing.
"The Nassib crossing will come under a Syrian civil administration, with Russian supervision," said Abazeed.
The border point, which has remained in opposition hands, is one of the key targets of the government's more than two-week offensive in southern Syria.
Recapturing it could bring renewed trade with neighbouring Jordan.
Abazeed said the preliminary deal also provided for the safe transfer of at least 6,000 people, including rebels and civilians, to the northwestern province of Idlib.
According to rebel sources, Moscow had previously rejected a phased surrender of heavy arms and any population transfers.
Ibrahim Jabbawi, another spokesman for the rebels' southern operations, confirmed the agreement on a ceasefire, the surrender of heavy weapons, and the rebel handover of the frontier road with Jordan.
A key ally of Damascus, Moscow has been brokering talks for the negotiated surrender of rebels in areas of southern Syria bordering Jordan and the Israeli-occupied Golan Heights.
The negotiations collapsed on Wednesday, ushering in a day-long volley of air strikes, barrel bombs and missiles that ultimately pressured rebels to return to the table.
They resumed talks at around midday on Friday. Rebels have walked away from negotiations in the past if they deem the terms too tough.