He said the summit would not take place on those days because of the COVID-19 pandemic.
Croatian Prime Minister Andrej Plenkovic as the chairman of the Council of the EU, European Council President Charles Michel and other partners are consulting about the possibility of holding a video conference at the most suitable time, Milic said.
The summit was planned as the main event of Croatia's presidency of the Council of the EU, which ends on June 30.
The Croatian presidency said earlier it had decided to postpone until May 15 at the earliest all informal meetings and conferences which were to have taken place in Croatia in order to curb the spread of the pandemic and alleviate its effects.