The terror outfit, in a statement released on Sunday, announced that dam, most commonly known as Euphrates Dam and located 40 kilometers upstream from Raqqah, is out of service due to airstrikes being carried out by the US-led coalition, and could collapse.

The statement said pressure on the dam’s compromised structure is building up rapidly as more water flow into the reservoir, bringing it up to its maximum capacity, while the sluice gates normally used to relieve that pressure are jammed shut.

Raqqah is Being Slaughtered Silently (RBSS), a group of citizen journalists who documents abuses in the Daesh stronghold, confirmed that the dam is not operational, saying people are fleeing Raqqah en masse in the wake of the looming collapse and consequent death toll.

The so-called and Britain-based Syrian Observatory for Human Rights (SOHR) also reported that Tabqa Dam is out of service.

Syrian official have warned that the collapse of earth-filled Tabqah Dam could inundate Raqqah as well the cities of Dayr al-Zawr and Abu Kamal, which lie 140 kilometers downstream from Raqqah.

Meanwhile, Daesh militant commander and three of his close aides have been killed during intense clashes with US-backed fighters from Syrian Democratic Forces (SDF) - a Kurdish-dominated and anti-Damascus alliance – near Tabqa Dam.

Local source identified the slain commander as German national Abu Omar al-Almani.

“Fighting is ongoing inside the airport and its surroundings. Full control of the airport is expected within the next few hours,” Talal Sello, a spokesman for the US-backed Kurdish-Arab alliance, said.

The Syrian Observatory for Human Rights monitor said IS forces had withdrawn from the airbase under heavy artillery fire and US-led coalition air strikes.

The SOHR said Daesh militants had withdrawn from the airbase under heavy artillery fire and US-led coalition airstrikes.

Separately, Syrian army soldiers have carried out a special operation against a gathering of Daesh terrorists in Beer al-Qasab area on the southeastern outskirts of Damascus, killing scores of the extremists and destroying their military equipment and munitions.

Syrian government forces, backed by the army air force, also pounded Daesh positions in Dayr al-Zawr suburbs, dealing heavy blows to the Takfiris.

Elsewhere in the southwestern province of Dara’a, army units targeted the positions of Nusra Front terrorists.