This is how Syria's President Assad bombed volunteer rescue workers in Douma

A video was posted to Facebook on Tuesday that claimed to show Syrian President Bashar al-Assad’s forces targeting voluntary rescue workers in a suburb of the capital Damascus.

A 90-second video showed members of the Syrian Civil Defence running through the streets of Douma searching for survivors after an airstrike by government warplanes hit the rebel-held city.

As the volunteers scoured the area for the wounded, a second strike hit the same location, and was caught on camera causing devastation.

The tactic of bombing a site, then targeting it again once people arrive to respond, is known as “double tapping,” according to the civil defence group.

More than 2,700 people volunteer with the Syrian Civil Defence, which was formed in 2013 and is also known as the White Helmets due to the headgear worn by its members when they are out responding to attacks across Syria.

On 16 August Douma was targeted in a series of strikes by the Syrian air force. At least 112 people were killed, in attacks the United Nations said could constitute a war crime.

According to the UN at least 230,000 people have been killed in Syria's brutal civil war, although the actual death toll is believed to closer to 300,000. More than 6.5 million people out of a population of 22 million have also been displaced by the conflict.