Islamic State group jihadists have blown up the Arch of Triumph in Syria's Palmyra, the country's antiquities chief said on Monday, stepping up their campaign of destruction at the world heritage site.

The move was seen as the latest salvo in the propaganda war being waged by the extremist group which has seized large parts of Syria and neighboring Iraq, committing atrocities including beheadings, rape and mass killings, and destroying archaeological and cultural heritage.

Syrian Antiquities Director Maamun Abdulkarim warned on Monday of a catastrophe unfolding in Palmyra, which the jihadists have been dismantling since capturing it in May.

"This is a systematic destruction of the city. They want to raze it completely," Abdulkarim told AFP.

"Every time IS has attacked, they acted like this."

He said IS had booby-trapped the Arch of Triumph, situated at the entrance to the ancient city's historic colonnaded street, several weeks ago and blown it up on Sunday.

The jihadist group had already destroyed several famed tower tombs, the 2,000-year old Temple of Bel, and the Lion of Athena.

Known as the "Pearl of the Desert", the ancient oasis town of Palmyra situated about 210 kilometers northeast of Damascus became famous as a stopping point for caravans traveling on the Silk Road.

Under IS' extreme interpretation of Islamic law, these artefacts are considered idolatrous, and must be destroyed.

'Maximizing infamy'

The jihadist group has also used the destruction of historic artefacts for propaganda, according to experts.

"It's a fairly low-risk, cheap way for IS to really maximize its international infamy," said Charlie Winter, analyst at the London-based Quilliam Foundation.

He said IS might have destroyed the celebrated arch as an attempt to recapture international attention after the Russian air strikes.

Experts say the militants have used the destruction to raise their profile to attract new recruits, and are also funding their "caliphate" by selling artifacts on the black market.

According to a political figure close to the Syrian government, "the Russians want to retake Palmyra to show that they are protecting heritage in Syria".

But as the Syrian army fights to recapture Palmyra, there are fears that the IS may speed up its razing of the ancient site.

For Winter, "the more the regime encroaches on Palmyra, the more likely it will be that it will be destroyed."

(China Daily 10/06/2015 page4)