IS has destroyed one of the most famous monuments in the ancient city of Palmyra.

Syrian antiquities chief Maamoun Abdulkarim said the armed group had blown up the Tetrapylon and the facade of its Roman Theatre.

The Palmyra site has changed hands between IS and Syrian government forces over the past few years.

IS militants have destroyed one of Palymyra's most famous monuments. Credit: AP

Government forces and their militia allies, backed by Russian air power, took back the city last March after first losing it in 2015.

But IS regained the UNESCO heritage site again in December.

During its occupation of the area, IS is believed to have destroyed several of the city's famed ancient Roman monuments as well as antiquities.