The Syrian Democratic Forces (SDF), dominated by terrorist PKK-affiliated People's Protection Units (YPG) Monday accused Russia of killing one of its fighters and wounding others in strikes on a gas facility it captured two days earlier in eastern Syria.

"Russian airstrikes and mortar fire hit the Conoco gas plant where a large number of our forces are stationed," SDF spokeswoman Lilwa Abdallah told AFP.

A statement issued later by the militia said one fighter had been killed and six wounded in the bombing.

Moscow neither confirmed nor denied the report, noting only that Russian warplanes were carrying out strikes on "terrorist sites" in support of regime operations against the terrorists in Deir el-Zour province.

Abdallah said Assad regime forces carried out additional bombardment of SDF positions after the initial Russian bombing.

"We reserve the right to respond," she added.

Russia is supporting the current offensive by the Assad regime forces against Daesh terrorist group near the city of Deir el-Zour with air cover, while Russian special forces are also active in the area.

Assad regime, backed by its ally Russia, is carrying out its own campaign against Daesh in Deir el-Zour, largely on the western side of the Euphrates, including in provincial capital Deir el-Zour city.

A "de-confliction" line is supposed to prevent the two campaigns from clashing, but Monday's alleged bombardment is the second time the SDF has accused Russia and the regime of hitting its fighters.

On Sept. 16, the group said six of its fighters were wounded in airstrikes by regime and Russian warplanes in the Al-Sinaaiya area around seven kilometers (4 miles) from the eastern bank of the Euphrates.

And on Sept. 21, Moscow warned Washington of reprisals after accusing the SDF of firing on Assad regime forces in the province.