The black marble plaque was placed in a public area in Solin's Priko Vode neighbourhood, in the immediate vicinity of a building with flats owned by war veterans. Flowers were placed and candles lit by the plaque.
The police, which was informed of the plaque at 4 pm, have not removed it yet. It is estimated the plaque was placed last night or early in the morning.
Mayor Zvonimir Hrgovic, who was informed of the plaque, was unavailable for comment.
County police said they were collecting information as to who placed the plaque and that they would not initiate its removal for the time being.