An opposition spokesman says that they could not accept Moscow's demands that they surrender before the implementation of any peace deal.
Negotiations between the Russians and Syrian rebels to end days of violence in the country's south collapsed on Saturday after opposition forces rejected surrender conditions proposed by Moscow, a rebel spokesman and a war monitor said.
Shortly after the collapse of negotiations over southern Syria, airstrikes intensified on rebel-held parts of Daraa province that borders Jordan.
TRT World's Staci Bivens reports
Saturday's talks came on the heels of similar negotiations which took place Friday, in which the Russians tabled their conditions to halt a Russian-backed government offensive to capture rebel-held areas along the borders with Jordan and the Israeli-occupied Golan Heights.
"The talks collapsed because the Russians insisted on their conditions that want us to surrender," said rebel spokesman Ibrahim Jabawi. "The (rebels') negotiating team refused to surrender and refused to accept the Russian conditions."
Rami Abdurrahman, who heads the Britain-based Syrian Observatory for Human Rights, a war monitor, also confirmed that the talks collapsed adding that shortly afterward Syrian and Russian warplanes intensified their airstrikes.
Syrian regime media said earlier Saturday that more areas in Daraa province had been captured and in others rebels had agreed to hand over their weapons and reconcile with the government.
The government offensive that began June 19 has killed scores of people, wounded hundreds of others and forced more than 50,000 to flee to areas close to the borders with Jordan and the Israeli-occupied Golan Heights.
Jabawi, spokesman for the rebels' joint operations room, said the insurgents set up a delegation that met with Russian officials Friday and again Saturday. He added that there are currently more efforts to hold a new round of talks to avoid further violence.
Jabawi told The Associated Press that Russia, a strong ally of President Bashar Assad's government, wants the rebels to hand over their weapons followed by a return of government forces to rebel-held areas.
Speaking by telephone from Jordan Jabawi said that the meetings with the Russians took place in an area near where the provinces of Daraa and Sweida meet.
"The Russian conditions are that rebels hand over everything and in return all areas will come under Bashar Assad's control," Jabawi said. "All people who carried arms will be put on trial."
Jabawi had said earlier Saturday that the Russian conditions "cannot be accepted" adding that to pressure the rebels, intense airstrikes have been targeting southern villages and towns that have until now largely evaded the violence of Syria's seven-year conflict.
The Observatory said the negotiations between rebels and the Russians were aimed to find "a full solution" for the future of Daraa.
It said negotiations aimed to reach a cease-fire as well as have rebels hand over their heavy weapons then later their light weapons. It added that in return for Russian guarantees, the rebels would hand over the Naseeb border crossing with Jordan and return state institutions to rebel-held areas in the south.
The Russians would also compile lists of rebels' names to work on securing them amnesty with the Syrian government.
The Observatory said that since the offensive began 11 days ago, 116 civilians have been killed including five on Saturday.
Jordanian government spokeswoman Jumana Ghunaimat said Amman is communicating with most of the parties to the Syrian crisis, mainly Russia and the US, in an attempt to reach a cease-fire.
"Jordan insists on its position that a political solution must end the Syrian crisis and it deals with relief organisations to help the displaced inside Syria," she said late Friday.