"I am not the biggest trade unionist. I am a politician and the president of a major party, and Mrs. Kosor should be the prime minister and not the prime trade unionist. In her office as Prime Minister, she can do much for Croatia, if she knows and wants," Milanovic said during a meeting of SDP members in Slavonski Brod.
Milanovic accused Kosor of missing a great opportunity to do something for Croatia a month ago when a revised budget had been prepared.
He said that the SDP would know how to bring order and justice to Croatia.
"We will do it. See you at the elections," the leader of the strongest opposition party said.