On 5 April 1944, the German occupation forces under the command of Karl Schümers, commander of the 7th regiment of the 4th Armored Division of the SS, the same unit to later that year commit the massacre in Distomo, slaughtered the women and children of Kleisoura in retaliation for the execution of three German soldiers by ELAS close to the village. The ELAS guerrillas, led by Alexis Rosios from Siatisti ("Captain Ypsilantis"), who were active in the region, had attacked a German military phalanx at Daouli, close to Kleisoura, and had killed a vanguard of three motorcyclists. According to testimonies, the male residents, fearing retaliation, fled to the mountains surrounding the village.