The commemorations are held in that eastern city because 28 of its children were killed during the 1991-95 war.
They are held with the support of the War Veterans Ministry, said Juliana Rosandić, president of a federation of civilian Homeland War victims.
Not one prime minister has attended a commemoration to date, yet the highest state officials should do so, she said.
"Over 400 children were killed in Croatia during the Homeland War, 28 in this city. That shows best all the shamelessness of the Greater Serbian aggression against Croatia", said Špiro Janović, state secretary at the ministry.
The law on civilian Homeland War victims was adopted because of the misfortune, sorrow and suffering of killed civilians' families, he said, adding that over 2,300 applications have been submitted for exercising the rights under this law and that 1,700 have been processed.
"Despite the politicking during its adoption, the law turned out to be good and aimed at victims' families. There were stories that there would be tens of thousands of applications and that the law would burden the state budget. None of that has happened," he said.
Numerous delegations laid wreaths at the Interrupted Childhood memorial, including envoys of President Zoran Milanović, Parliament Speaker Gordan Jandroković and Prime Minister Andrej Plenković.