So-called Islamic State militants have beheaded four people and shot eight dead in the Syrian city of Palmyra, a monitoring group says.
Some of the killings took place in a museum yard near the city's Unesco-listed ancient ruins, the Syrian Observatory for Human Rights said.
Four teachers and state employees, four government soldiers and four captured rebels were killed, it added.
IS retook the site and nearby city last month, after being pushed out in March.
A report from a local activist group, the Palmyra Monitor, said some of the killings were carried out in the site's Roman amphitheatre.
The group has previously carried out killings in front of crowds in the ancient stone auditorium, including 25 Syrian government soldiers who were shown being shot dead in a video released in 2015.
In August the same year, the jihadists also beheaded the 81-year-old archaeologist, Khaled al-Asaad, who had looked after the Palmyra ruins for 40 years.
IS had seized control of the archaeological site and nearby city, known locally as Tadmur, three months earlier.
They destroyed a number of monuments and, according to the UK-based Syrian Observatory for Human Rights, killed an estimated 280 people in the 10 months before Russian-backed government forces recaptured the area.
A Russian conductor led a classical concert in the amphitheatre in May 2016.
But while forces allied to President Bashar al-Assad were focused on battling for the city of Aleppo in December, the militants returned and regained control.
US-backed Iraqi forces have pushed the Islamic State group out of large swathes of northern Syria and Iraq in the past year and have been battling to retake the city of Mosul in northern Iraq since October.
On Wednesday, a Russian Defence Ministry official, Lt Gen Sergei Rudskoi, said the Mosul offensive was pushing IS fighters back into eastern Syria.
He said the Islamic State group was shipping large amounts of explosives to Palmyra in order to blow up more of the heritage site.