BEIRUT - ISIS has destroyed the facade of the ancient Roman theater of Palmyra, in central Syria, and the Tetrapylon, a colonnaded structure at the archaeological UNESCO world heritage site, Syria's official news agency Sana reported on Friday, without providing further details.

The Sana news agency quoted unnamed ''local sources'' in reporting about the destruction at Palmyra's Roman amphytheater. The report cannot be independently verified. Over the past few days, the Syrian Observatory for Human rights said that ISIS has killed 12 civilians and pro-government militants on the stage at the theater.

The execution was similar to one in 2015 when over 20 Syrian soldiers were killed by teenagers who were alleged members of the terror organization at the UNESCO world heritage site, according to the monitoring group.