Syrian activists say the Islamic State militants, after seizing the ancient town of Palmyra in central Syria, are now also in full control of its famed archaeological site.

Rami Abdurrahman of the Britain-based Syrian Observatory for Human Rights says the extremists overrun the site, just to the southwest of Palmyra, shortly after midnight Wednesday.

An activist in the central province of Homs who goes by the name of Bebars al-Talawy also says that IS now controls the ruins at Palmyra, a UNESCO world heritage site famous for its 2,000-year-old towering Roman-era colonnades and other ruins and priceless artifacts.

Both activists said Thursday that IS has not damaged the ruins so far. There are fears the extremists would destroy the ruins as they did major archaeological sites in Iraq.