Islamic State militants have executed at least 400 mostly women and children in Syria's ancient city of Palmyra.
Eye-witnesses have reported the streets are strewn with bodies - the latest victims of the Islamic State's unrelenting savagery - on the same day photographs of captured Syrian soldiers have emerged.
It follows the killing of nearly 300 pro-government troops two days after they captured the city, now symbolised by a black ISIS flag flying above an ancient citadel.
ISIS has also strengthened its position in neighbouring Iraq with Jihadi fighters killing more than 500 people when they captured the city of Ramadi, last week.
Syrian state television announced the most recent massacre, quoting residents inside the city, which is known as Tadmur in Arabic.
"The terrorists have killed more than 400 people.. and mutilated their bodies, under the pretext that they cooperated with the government and did not follow orders," Syria's state news agency said.
It added that dozens of those killed were state employees, including the head of nursing department at the hospital and all her family members.
Harrowing pictures have also emerged of Syrian army troops captured during the fierce fighting as the city fell. The 20 soldiers, in military clothing, look disheveled as they kneel before cameras.
Officials say the Syrian army is deploying troops in areas near to the ancient town in apparent preparation for a counter-attack to retake the city from the Islamic State group.
Governor Talal Barazi of the central province of Homs, which includes Palmyra, said that IS members have "committed mass massacres in the city of Palmyra" since its capture.
He said IS fighters took civilians, including women, to unknown destinations.
But he said retaliation was imminent, adding: "There is planning, God willing, for a military action in the surroundings of Palmyra."
It comes as a former head of the Army called on the Government to "think the previously unthinkable" and consider sending ground troops to combat Islamic State (IS) in Syria and Iraq.
Lord Dannatt, the former chief of the general staff, told the Mail on Sunday he felt air strikes had failed to stop the advance of the extremist organisation and urged Parliament to debate deploying up to 5000 infantry soldiers.
"In light of this terrifying scenario, how much longer can Britain and the US continue to show such a lack of commitment to defeating IS mililtarily? Their default option of air strikes and limited assistance to indigenous forces has failed thus far," he said.
"We have now reached a point when we must think the previously unthinkable and consider that British troops, acting as part of an international coalition, may be required to mount a ground campaign in Iraq and Syria.
"I am no gung-ho general who says, 'Just send the boys in and don't worry about the body bags', far from it, but faced with such a lethal and uncompromising enemy as IS - and with the lack of political and diplomatic solutions at our disposal - we can no longer rule out 'boots on the ground'."
Meanwhile, US defence secretary Ash Carter criticised Iraqi forces for not having the 'will to fight' after the Islamic State group's takeover of Ramadi.
Mr Carter said the United States can provide training, weapons and air support in the fight against the Islamic State extremists but he said the Iraqi forces will have to show a willingness to fight for their country.
"What apparently happened is the Iraqi forces just showed no will to fight. They were not outnumbered," he said.
"In fact, they vastly outnumbered the opposing force. That says to me, and I think to most of us, that we have an issue with the will of the Iraqis to fight ISIL and defend themselves."
Now the terror group also has full control of Palmyra, putting the world heritage site and its priceless 2000-year-old artefacts at risk of destruction.
The city is home to renowned Roman-era ruins including well-preserved temples, colonnades and a theatre.
Opposition activists have said on social media that hundreds of bodies were in the streets of the city after it was seized by the ultra hardline group on Wednesday. They said they were believed to be government loyalists.
- Daily Mail