SOHR chief Rami Abdel Rahman states that the attack was aimed at a meeting between leaders of various allied terror groups in connection with a training camp.

Initially, there was uncertainty about who carried out the attack, but later on Saturday, the US Department of Defense declared that US forces were behind.

Last strong rebel bracket

The US attack came just hours after a four-month government offensive against Idlib was suspended after a ceasefire backed by Russia came into force, SOHR reports.

Since the end of April, the Syrian military, supported by Russia, has carried out a comprehensive offensive against Idlib, which is the last stronghold of the rebels in the country.

More than 950 civilians have been killed in air strikes during the offensive, according to SOHR.