Militants from the Islamic State group (IS) have blown up the Arch of Triumph, a major monument in the 2,000-year-old Roman city of Palmyra, Syria's antiquities chief says.

Maamoun Abdulkarim said sources in Palmyra had confirmed that the Arch of Triumph, a jewel in the exquisite collection of ruins in the oasis city, had been blown up.

"We have received news from the site that the Arch of Triumph was destroyed yesterday. IS bobby-trapped it several weeks ago," he said.

Situated at the entrance of the ancient ruins' historic colonnaded street, it was an "icon of Palmyra", Mr Abdulkarim said, warning that IS fighters have already laid explosives in other monuments.

"This is a systematic destruction of the city. They want to raze it completely," he said.

"They want to destroy the amphitheatre, the colonnade. We now fear for the entire city," he added, calling on the international community to "find a way to save Palmyra".

Mohammad Hassan al-Homsi, an activist from Palmyra, backed up the account, saying: "The Arch of Triumph was pulverised. IS has destroyed it."

What is Palmyra? UNESCO describes Palmyra as a heritage site of "outstanding universal value"

UNESCO describes Palmyra as a heritage site of "outstanding universal value" Palmyra first entered recorded history in the early second millennium BC as a caravan stop for travellers

Palmyra first entered recorded history in the early second millennium BC as a caravan stop for travellers The ancient city stood on a caravan route at the crossroads of several civilisations; the place where the ancient Greek and Roman worlds met the ancient Persian and Parthian worlds on the Silk Road

The ancient city stood on a caravan route at the crossroads of several civilisations; the place where the ancient Greek and Roman worlds met the ancient Persian and Parthian worlds on the Silk Road Its first and second century temples and colonnaded streets mark a unique blend of Graeco-Roman and Persian influences

Its first and second century temples and colonnaded streets mark a unique blend of Graeco-Roman and Persian influences It is strategically important, placed in the centre of the Syrian desert, and is the crossroads for roads going to Jordan, Iraq, and Damascus.

Citing sources on the site, the Syrian Observatory for Human Rights monitoring group said the militants had destroyed the arch because of ornaments on its columns the group considered idolatrous.

Jihadists blew up temples at the Roman-era UNESCO World Heritage site, which it has controlled since capturing Palmyra from Syrian government forces in May, and mined other monuments and historic buildings.

The Islamist extremist group considers the buildings sacrilegious.

"It's as though there is a curse that has befallen this city and I expect only news that will shock us," Mr Abdulkarim said.

If the city remains in their hands the city is doomed.

"It is now wanton destruction ... their acts of vengeance are no longer ideologically driven because they are now blowing up buildings with no religious meaning."

The militants beheaded the 82-year-old guardian of Palmyra's ancient ruins in August.

In the same month, they blew up the temple of Baal Shamin, then the Temple of Bel, one of the best preserved Roman-era sites.

It was also confirmed the militants had destroyed some of the best preserved of Palmyra's funeral towers, sandstone constructions built to hold the remains of the ancient city's richest families.

Palmyra was one of the most important cultural centres of the ancient world, according to cultural agency UNESCO, which has described it as the crossroads of several civilisations.

Islamic State has declared a caliphate in territory it holds across Syria and Iraq and has destroyed other monuments it says are pagan and sacrilegious.

UNESCO has called such acts war crimes and says Islamic State seeks to wipe out evidence of Syria's diverse heritage.

Before the capture of the city, Syrian officials said they had moved hundreds of ancient statues to safe locations.

Map Map of temples in Palmyra's heritage site

Reuters