Dubravka Špoljarić (17) and Josipa Špoljarić (18), who were staying at the refugee camp Grabovac, also lost their lives when Serb forces shelled the camp from the nearby hills.
The three children and their mothers had fled their village of Korana in the Plitivce Lakes area to seek shelter in the refugee camp.
Today's commemorative event included wreath-laying ceremonies and prayers.