The group in control of the last rebel bastion near Damascus appeared on Sunday to have agreed a deal for its fighters to make peace with the government or quit the eastern Ghouta enclave, Syrian state media said.
Jaish al Islam, most of whose members are drawn from the area, has been defending the city of Douma against a months-long onslaught by government forces.
If confirmed, its surrender or departure for rebel-held areas in northwest Syria would herald an end to large-scale conflict in the enclave.
State television and Syrian newspapers said information indicated that, under the deal, the group would hand over heavy and mid-sized weapons and acknowledge the restoration of state sovereignty over Douma.
A Hezbollah run-media unit said on Sunday an agreement had been reached after several days of negotiations to spare bloodshed in Douma.