DAMASCUS (AFP) - Islamic State in Iraq and Syria militants on Sunday (Aug 23) blew up the ancient temple of Baal Shamin in the Unesco-listed Syrian city of Palmyra, the country's antiquities chief said.

"Daesh placed a large quantity of explosives in the temple of Baal Shamin today and then blew it up causing much damage to the temple," Mr Maamoun Abdulkarim told AFP, using another name for ISIS.

Famed for well-preserved Greco-Roman ruins, Palmyra was seized from government forces in May, fuelling fears the ISIS militants might destroy its priceless heritage as it had done in other parts of Syria and Iraq.

Until Sunday, most of Palmyra's most famous sites had been left intact, though there were reports ISIS had mined them and the group reportedly destroyed a famous statue of a lion outside the city's museum.

ISIS, which controls swathes of Syria and neighbouring Iraq, captured Palmyra on May 21, sparking international concern about the fate of the heritage site described by Unesco as of "outstanding universal value".

"The cella (inner area of the temple) was destroyed and the columns around collapsed," he said.

The Syrian Observatory for Human Rights, a Britain-based group that monitors the country's civil war, confirmed the destruction of the temple.

Baal Shamin was built in AD17 and it was expanded under the reign of Roman emperor Hadrian in AD130.

Known as the "Pearl of the desert", Palmyra, which means City of Palms, is a well-preserved oasis 210km north-east of Damascus.

Its name first appeared on a tablet in the 19BC as a stopping point for caravans travelling on the Silk Road and between the Gulf and the Mediterranean.

But it was during the Roman Empire - beginning in the first century BC and lasting another 400 years - that Palmyra rose to prominence.

Before the arrival of Christianity in the second century, Palmyra worshipped the trinity of the Babylonian god Bel, as well Yarhibol (the sun) and Aglibol (the moon).

"Our darkest predictions are unfortunately taking place," said Mr Abdulkarim.

The militants "carried out executions in the ancient theatre of Palmyra, they destroyed in July the famous Lion Statue of Athena... and transformed the museum into a prison and a courtroom".

ISIS had mined the ancient site in June before destroying the Lion Statue of Athena - a unique piece made of limestone that stood more than 3m high that stood outside a museum.

Funerary busts were also destroyed by ISIS in Palmyra.

ISIS' harsh version of Islam considers statues and grave markers to be idolatrous, and the group has destroyed antiquities and heritage sites in territory under its control in Syria and Iraq.

The latest developments come just days after ISIS militants beheaded the 82-year-old retired chief archaeologist of Palmyra.

On Sunday (Aug 23), the family of Khaled al-Assaad said the militants had mutilated his body after killing him execution-style on Tuesday.