More to follow.

(AP) – Syrian activists say Islamic State group militants have shot dead a group of detainees in the Roman theater in ancient ruins of Palmyra.

They say Islamic State gunmen killed at least 15 men after accusing them of having fought with President Bashar Assad’s troops.

The incident — the first since the group captured the historic town in central Syria earlier this month — was reported by activists belonging to a Palmyra-based media collective and the Britain-based Syrian Observatory for Human Rights.

They said the militants gathered people in the theater to watch. The theater is part of the 2,000-year-old Roman-era ruins in Palmyra.