BEIRUT -- Islamic State militants have destroyed parts of the second-century Roman amphitheater and a revered monument known as the Tetrapylon in Syria's historic town of Palmyra, the government and experts said Friday.
It was the extremist group's latest attack on world heritage, an act that the U.N. cultural agency called a "war crime." A Syrian government official said he feared for the remaining antiquities in Palmyra, which the Islamic State recaptured last month.
The United Nations Security Council "strongly condemned the ongoing barbaric attacks" by the militant group in Syria, "including the destruction of cultural heritage such as parts of the Roman Theater in Palmyra."
After suffering several setbacks in Syria, the Islamic State has gone on the offensive -- reclaiming ancient Palmyra in December and launching an attack on a government-held city and military air base in Deir el-Zour in eastern Syria.
On Friday, Syria Arab News Agency said seven civilians were killed when Islamic State extremists shelled a residential area in the city of Deir el-Zour.
Palmyra, a UNESCO world heritage site that once linked Persia, India and China with the Roman empire and the Mediterranean area, has already seen destruction at the hands of the Islamic State group. The ancient town first fell to Islamic State militants in May 2015, when they held it for 10 months. During that time, the extremist group damaged a number of its relics and eventually emptied it of most of its residents.
Palmyra fell again to the group last month, only nine months after a Russian-backed Syrian government offensive was hailed as a significant victory for Damascus.
On Friday, Maamoun Abdulkarim, the head of Syria's antiquities department, said reports of the recent destruction first trickled out of the Islamic State-held town late last month. But satellite images of the damage to the Tetrapylon only became available late Thursday, confirming the destruction.
Extremists have destroyed ancient sites across their self-styled Islamic caliphate in Syria and Iraq, perceiving them as monuments to idolatry.
"The Tetrapylon was an architectural symbol of the spirit of the encounter and openness of Palmyra -- and this is also one of the reasons why it has been destroyed," Abdulkarim said in a statement.
The militants also blew up the Arch of Triumph, built between A.D. 193 and A.D. 211.
Abdulkarim said he fears for what remains of the city's ancient relics.
"When Palmyra fell for the second time, we shed tears because we expected this terror," he said. "Now we are destined to see more terror if [Islamic State control of Palmyra] continues."
Palmyra, with its 2,000-year-old towering Roman colonnades and priceless artifacts, was affectionately referred to by Syrians as the "Bride of the Desert."
Information for this article was contributed by Lori Hinnant and Vladimir Isachenkov of The Associated Press.
A Section on 01/21/2017