The Syrian army is deploying troops in areas near the ancient town of Palmyra in apparent preparation for a counterattack to retake it from the Islamic State group, an official said.

Gov. Talal Barazi of the central province of Homs, which includes Palmyra, told The Associated Press Sunday that IS members have "committed mass massacres in the city of Palmyra" since they captured it on Wednesday. He said IS fighters took many civilians, including women, to unknown destinations.

Activists in the town have said that IS fighters have hunted down President Bashar Assad's loyalist since taking the town, killing some 280 people.

Syria's Prime Minister Wael al-Halqi condemned what he called "a massacre" in Palmyra blaming Saudi Arabia, Qatar and Turkey for such killings because of their support for groups trying to remove Assad from power.

Al-Halqi called on the international community and all humanitarian organizations to pressure the governments that support "terrorism" to stop their support "as terrorism is posing a global danger." Saudi Arabia, Turkey and Qatar are main backers of Syrian rebels and opposition groups.

Barazi, the governor, said troops are fighting with IS gunmen in the nearby Jizl area. "There are plans, but we don't know when the zero hour for a military act in Palmyra," Barazi said without elaborating.

Meanwhile state-run news agency, SANA, said IS members are still preventing people from leaving Palmyra. The U.N. refugee agency, UNHCR, said that along with its partners they are preparing aid for some 11,000 people who fled Palmyra and surrounding villages.

A Facebook page used by IS to publish its statement posted a photo of 20 Syrian soldiers in uniform captured in Palmyra.

The capture of Palmyra has stoked fears that the militants might try to destroy one of the Mideast's most spectacular archaeological sites - a well-preserved, 2,000-year-old Roman-era city on the town's edge - as they have destroyed others in Syria and Iraq.