Women and children are among 400 executed by Isis in Palmyra
Isil fighters have executed at least 400 people, including many women and children, in Palmyra since capturing the ancient Syrian city, Syrian state media has claimed.
It was not immediately possible to verify the account, but it was consistent with reports by activists that the Islamist fighters had carried out executions since capturing the city from government troops.
The Isil militants seized the city of 50,000 people, site of some of the world's most extensive ancient Roman ruins, on Wednesday, days after also capturing the city of Ramadi in neighbouring Iraq.
The two near-simultaneous victories were Isil's biggest successes since a US-led coalition began an air war against the fighters last year.
The Sunni Muslim militants have proclaimed a caliphate to rule over all Muslims from territory they hold in both Syria and Iraq. They have a history of carrying out mass killings in towns and cities they capture, and of destroying ancient monuments which they consider evidence of paganism.
"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 the nursing department at the hospital and all her family members.
Isil supporters have posted videos on the internet they say show fighters going room to room in government buildings searching for government troops and pulling down pictures of President Bashar al-Assad and his father.
Activists have said on social media that hundreds of bodies, believed to be government loyalists, were lying in the streets.
The Syrian Observatory for Human Rights, which monitors violence in the country with a network of sources on the ground, says that some people were beheaded in the town since it fell but has not given an estimate for the toll among civilians.
It says at least 300 soldiers were killed in the days of fighting before the city was captured.
"A bigger number of troops have disappeared and it is not clear where they are," Rami Abdulrahman from the Observatory said.
US Defence Secretary Ashton Carter accused Iraq's army of abandoning Ramadi to a much smaller enemy force.
"The Iraqi forces just showed no will to fight," he said yesterday. "They vastly outnumbered the opposing force, and yet they withdrew from the site."
Iraq's government and its allies launched a counter-offensive on Saturday, a week after losing Ramadi.
A police major and a pro-government Sunni tribal fighter in the area said they had retaken the town of Husaiba al-Sharqiya, about 10km east of Ramadi.