IS conducts its largest mass murders of 2017

IS murdered 33 people in Syria early Wednesday morning in what has been described as the largest mass execution since 2016.

The mass killings of the men aged between 18 and 25 took place in the al-Mayadin desert, near the city of Deir az-Zor, according to the Syrian Observatory for Human Rights (SOHR) monitoring group. 

The victims were "slaughtered" with sharp knives, the observer group said in its report, adding that some of its activists had witnessed the gruesome process.

They said the mass killings were carried out close to a mass grave and was "filled with blood". The victims' throats were slit and they were left to bleed to death.

"No one of the 33 slaughtered persons was beheaded, also no one of the executed bodies was identified," the Syrian observatory added.

"It is not known whether they were members of the regime forces and militiamen loyal to them or if they were fighters of the factions, or whether they were prisoners who were sentenced to be 'executed' by the organisation after arresting them earlier."

The Syria war began in 2011, when peaceful protests demanding democratic reforms were brutall crushed by regime forces.

According to independent monitors, hundreds of thousands of civilians have been killed in the war the vast majority by the regime and its powerful allies.

Millions more have been displaced both inside and outside of Syria.

The brutal tactics pursued mainly by the regime have included the use of chemical weapons, bombings, sieges, mass executions and torture against civilians.