BEIRUT — Islamic State fighters have pushed into the Syrian town of Palmyra, home to famed 2,000-year-old ruins, and are clashing with government troops in residential areas.

The militants entered from the north and have not reached the UNESCO world heritage site, which is southwest of Palmyra.

A rare 2nd century limestone tablet unearthed in the central ancient city of Palmyra. The Associated Press

The ISIS push on the town in the central Homs province, which began on Thursday, has raised alarm in Syria and abroad. The group is notorious for destroying archaeological sites in neighboring Iraq. Palmyra, with its Roman-era colonnades, is one of the most famous world heritage sites in the Middle East. The U.N. cultural agency chief Irina Bokova expressed alarm Friday over the clashes.

The Syrian Observatory for Human Rights and activist Bebares al-Talawy said the militants were clashing with government troops in the northern part of the town on Saturday. The Observatory said ISIS fighters have seized control of parts of the town.

Al-Talawy said government forces still control the airport in the town’s northeast.