(CNN)Syrian troops have entered the ancient city of Palmyra and are poised to retake it from ISIS militants, Syrian state media reported Thursday.
State TV broadcast images that purportedly show government forces entering the southwestern part of the city, while a TV anchor said the army is "close to announcing that Tadmur" -- another name for the area around Palmyra's historic ruins -- "has been cleared of ISIS terrorists."
ISIS took over the central Syrian city in May, expanding its conquests in the region and showing its contempt for the people and their history.
20 photos: 20 precious monuments destroyed by war
By June, the Islamic extremist group began destroying historical sites. The Syrian government said ISIS destroyed two Muslim holy sites: a 500-year-old shrine and a tomb where a descendant of the Prophet Mohammed's cousin was reportedly buried.
Two months later ISIS destroyed more antiquities, including the 1,800-year-old Arch of Triumph that framed the approach to the city and the nearly 2,000-year-old Temple of Baalshamin. ISIS also beheaded the antiquities expert who looked after the ruins.
UNESCO, the U.N. agency that compiles a list of the world's most important cultural and natural sites, called the temple's destruction a war crime.
Palmyra, in the Homs countryside northeast of Damascus, was a caravan oasis when Romans overtook it in the mid-first century. In the centuries that followed, the area "stood at the crossroads of several civilizations" with its art and architecture mixing Greek, Roman and Persian influences, according to UNESCO.
ISIS says it's still in control
After the news that Syrian troops were poised to retake Palmyra, ISIS released a video to prove it still controls the city.
The video shows the city's deserted streets and then cuts to an ISIS militant sitting on a tank, in an indistinctive desert location, saying the group will defeat any forces that try to enter the city. Also in the video is a panoramic shot of Palmyra's ruined historical site, taken from a distance.
CNN cannot independently verify the video's authenticity.
Thursday's reported advance by Syrian troops comes a day after they captured a strategic hilltop on Palmyra's outskirts, according to state media and the Syrian Observatory for Human Rights, a London-based monitoring group.
The observatory said Thursday that Syrian troops were clashing with ISIS fighters while receiving help from Syrian and Russian warplanes. The troops were a few hundred yards from a main southwest entrance into the city, the group said.
The official Syrian Arab News Agency reported Thursday that Syria's army took over three locations west of Palmyra -- al-Qubour Valley, al-Qusour Mountain and al-Tar Mountain -- and that troops "eliminated, to the last one" all ISIS factions in that area.
The agency cited a military source.
The Syrian army "killed or injured all ISIS terrorists at Dedeman Hotel" and at a roundabout near Palmyra's southwestern entrance, according to the same report.
History destroyed
Irina Bokova, of UNESCO, praised the news that Syrian troops had entered the city.
"I welcome the liberation of the Palmyra archeological site, martyr city inscribed on the UNESCO World Heritage List, which carries the memory of the Syrian people, and the values of cultural diversity, tolerance and openness that have made this region a cradle of civilization," she said in a statement.
Among the other ISIS-destroyed historical sites in Palmyra are the Temple of Bel, which dated to 32 A.D.; the 1,900-year-old lion statue that stood at the entrance to the city's museum; and three ancient tower tombs dating as far back as 44 A.D, including the Tower of Elahbel, built in 103 A.D. and regarded as the finest example of this type of building, SANA reported.
"For one year, Palmyra has been a symbol of the cultural cleansing plaguing the Middle East," Bokova said.
Updated 2254 GMT (0654 HKT) March 24, 2016
