Engineers working to open spillways in a major Syrian dam partly held by Daesh in Raqqah province have had to evacuate the site after the extremists shelled it following US airstrikes.

A witness told Reuters that Daesh lobbed a barrage of mortars from the southern end of Tabqa Dam, most commonly known as Euphrates Dam and located 40 kilometers upstream from Raqqah, causing at least two explosions.

The engineers were reportedly trying to open spillways to drain excess water and relieve pressure behind the dam.

Daesh, in a statement released on Sunday, announced that Tabqa Dam was out of service due to airstrikes carried out by the US, and could collapse.

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

People stand at the northern part of Tabqa Dam on the Euphrates River, Syria, on March 28, 2017. (Photo by Reuters)

On Tuesday, Lieutenant General Sergei Rudskoi of the Russian military's General Staff leveled strident criticism against the US over pounding the dam that lies 40 kilometers west of Daesh’s main stronghold of Raqqah.

The high-ranking Russian military figure argued that the military contingent was trying to “completely destroy critical infrastructure in Syria and complicate post-war reconstruction as much as possible.”

Read more:

Minibus bombing leaves 5 dead in western Syria

Meanwhile, at least five people lost their lives when a bomb went off on a minibus in Syria’s western city of Homs, located 162 kilometers north of the capital Damascus, on Wednesday noon.

Local sources told Syria's official news agency SANA that the attack took place on al-Settin Street in the city's al-Zahra neighborhood.

This undated picture provided by Syria's official news agency SANA shows the aftermath of a double bomb attack in the western Syrian city of Homs.

Director of the Homs Health Directorate Dr. Hassan al-Jundi said ambulances transported five bodies and six wounded people to hospitals in the city.

On March 14, a bomb blast on a passenger bus in the Wadi al-Zahab neighborhood of Homs left six people injured.