The Islamic State (Isis) terrorists have beheaded a noted Palmyra historian and archaeologist, Khaled Asaad. He was arrested a month ago.

Isis reportedly arrested Asaad for his role in moving valuable statues out of Palmyra before the terrorist group took over the UNESCO heritage site in May.

By removing hundreds of statues and artifacts out of the city on time, Asaad ensured that they were safe from being destroyed by Isis.

Isis militants after beheading the 82-year old head of Palmyra archaeological department, put his decapitated body on the streets of Tadmur. Isis also hung a board over his body detailing his crime of being a traitor, who colluded with the Syrian army.

Asaad, who is known for his scholarly work, had worked for the last 50 years assisting US, French, German and Swiss archaeological missions in Palmyra.

Syrian state antiquities chief Maamoun Abdulkarim confirmed to media the family of Khaled Asaad was executed on Monday. His body was left on the streets for the last two days.

It is believed that Isis was angry at Asaad for assisting the Syrian forces in moving the "valuable statues" out of the city of Tadmur.

Isis captured the 2,000 years old UNESCO heritage on 21 May and since then, there has been much concern over the safety of the ancient site. In recent months, Isis has carried out several beheadings in the ancient city. In July, 25 Assad-loyal soldiers were shot and killed by teenagers, who were part of Isis.

In July, on the eve of Eid ul Fitr, Isis used a child to behead a Syria Army captain.