Fighters from the militant group ambushed the group of soldiers and then executed the majority of them after capturing them
The deaths were reported in Raqqa on Friday. The city is an Islamic State stronghold. The killings came only a day after the jihadist group launched a fierce assault on the 17th Division of the army.
The fighting left more than 50 soldiers dead and as many as 28 members of the Islamic State group said the Syrian Observatory for Human Rights a right group that is based in the United Kingdom.
Due to restrictions of reporting directly inside Syria, it is hard for most media outlets to verify information. However, media close to the President Bashar al-Assad regime were silent about the Raqqa deaths.
The rights group told reporters that some of the soldiers killed in the battle died during the fighting, but most were beheaded.
An account on Twitter that is linked to the Islamic State published pictures of corpses that had been beheaded and the heads of five Syrian soldiers in Raqqa.
The ambush and subsequent assault on the troops was a rare confrontation of such a fierce magnitude between government forces from Syria and the fighters from Islamic State.
The Islamic State militant group, which has proclaimed caliphate in a region that spans the Iraqi and Syrian borders during June. It controls huge stretches of land on both sides of the border and is looking to extend its influence and power.
Previously the group was called the Islamic State in Iraq and the Levant and has mainly been able to advance inside Syria through capturing land from rebel fighters that are more moderate.
However, it now clashes more frequently with the military in Syria and the Syrian army has stepped up its aerial bombings on the group’s positions.
Last week, Islamic State fighters killed 270 guards, staff and soldiers after capturing a central Syria gas field.