Daesh jihadist group shot dead at least 20 men in the ruins of Syria's ancient city Palmyra Wednesday, accusing them of fighting for the government, a monitoring group said.

"Daesh executed 20 men by firing on them in front of a crowd gathered in Palmyra's Roman theatre, after accusing them of fighting for the Syrian regime," Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, told AFP.

"Daesh gathered a lot of people there on purpose, to show their force on the ground," Abdel Rahman said.

Daesh has carried out a string of atrocities including videotaped beheadings and mass killings, rape and enslavement in areas it controls in Syria and neighbouring Iraq.

Daesh seized Palmyra, including its UNESCO world heritage site, on May 21, after a bloody assault that lasted nine days.

The Britain-based Observatory said Daesh had executed at least 217 people, including 67 civilians, in and around the city.
Source: AFP