Chadian soldiers, who said the bodies were discovered on Thursday, spoke of at least 100 corpses in the area around the dry river bed.
In what appeared to be an execution site for the terrorists, the bodies were strewn beneath the concrete bridge on one of the main roads leading out of the town. At least one was decapitated.
The bodies were partially mummified by the dry desert air, while grass has began to grow around the corpses, suggesting that the killings had taken place some time ago.
A strong smell of decomposition in many parts of town suggested there could be more bodies concealed there, the Reuters witness said.
A trail of blackened blood was visible along the side of the bridge facing the bodies, suggesting they had been thrown off the side after being killed. Among the dead was the imam of the town.
All but around 50 of the town's residents had fled by the time Damasak was recaptured. Those who remained were mostly too old or too sick to leave.
