Syria says its forces have fought their way into Palmyra, the ancient city held for nearly a year by Islamic State insurgents who destroyed many of its Roman-era antiquities.
Syrian state television said Thursday that government troops backed by Russian warplanes pushed into the city. Islamic State fighters used loudspeakers to warn civilians to leave as the fighting intensified.
The state news agency SANA showed Russian planes flying above the city, helicopters firing missiles and soldiers and armored vehicles advancing.
Palmyra, a UNESCO world heritage site known as the "Pearl of the Desert," has been held by Islamic State since May.
To widespread condemnation, the insurgents blew up many of the city's world-renown relics, including the 2,000-year-old Temple of Bel and the iconic Arch of Triumph, and looted centuries-old artifacts.
The head of Syria's antiquities and museum's agency, Maamoun Abdulkarim, said he hoped the government's advance on the city would end the "nightmare" of last year's Islamic State takeover. He called the fight for Palmyra a "cultural battle for the entire world, and everyone who believes in common human heritage."
The Syrian broadcast said fighting is occurring near one of the archaeological sites. One soldier said he had a message for the Islamic State fighters: "You will be crushed under the feet of the Syrian Arab Army."
Palmyra's one-time population of 70,000 dwindled to 15,000 under Islamic State rule. The extremists' harsh tactics, including public beheadings of supposed opponents, sparked the exodus.
The British-based Syrian Observatory for Human Rights, which monitors fighting in Syria with frontline accounts from inside the country, said most of the residents fled before the government assault this week. "Only those too poor to flee stayed behind," the monitoring group said.
If forces loyal to Syrian President Bashar al-Assad regain control of Palmyra, it would be a strategic as well as symbolic victory, since the city is the gateway to the vast desert extending from central Syria to the Iraqi border.