Syrian forces and pro-Iran militias heightened an offensive against a rebel enclave in a southwestern region on the border with Jordan and Israel, military and opposition sources say.
Witnesses and military sources said dozens of improvised missiles were fired on August 31 into Deraa al-Balaad by the Syrian military's pro-Iran Fourth Division.
Fighting has escalated this week after the collapse of a peace deal brokered by Russia designed to avert a major offensive against Deraa al-Balaad.
The city has remained outside of Syrian government authority since surrounding Deraa Province was recaptured by Syrian President Bashar al-Assad's forces in 2018.
Russian military officials have offered a new plan that appeared to meet some rebel demands to involve the Russian military police in the patrolling of the enclave and, for the first time, allow a Syrian military presence in the area.
Military sources said Iran-backed troops that have encircled the rebel stronghold for the last two months would be withdrawn under the deal.
Syrian forces, supported by Russian air power and Iran-backed militias, retook Deraa Province in 2018.
Moscow assured Israel and the United States at the time that it would prevent Iran-backed militias from encroaching on the border zone.
Russia, along with Iran, has provided crucial military support to Assad in the Syrian conflict, which began with a crackdown on anti-government protesters in March 2011. More than 400,000 people have since been killed and millions displaced.