"Every such act of terror must be condemned," he said in Vojnic, some 50 kilometres south of Zagreb, on Thursday, adding it was up to the police to find and the judiciary to punish the perpetrators.
Mesic also said that such incidents in formerly war-struck areas disturbed the peace established there.
Asked about forthcoming presidential elections, he said he was fine with any date of the polls since "I will defeat any opponent anyway, because I know what does and what doesn't need to be done in this country so we can live in a calmer and civilised climate".
Asked if he made mistakes in his current term, Mesic said there were no strategic mistakes. He added the fact that he sent a number of generals into retirement was considered a mistake.
"If I hadn't done that, the military would have interfered in politics and who knows how we would live today," he said, adding that politics was too serious a business for generals to be involved in it.
Mesic went on to say that if he won the presidential race, his main challenges would be the rule of law, making all citizens equal in rights and interests, and adopting European standards. He said joining the European Union would then follow in the logic of things.
While visiting the nearby Cetingrad, the President met representatives of the Bosnian Muslim minority and the Islamic community. He said he would consider the fact that 129 local Bosnian Muslims still do not have Croatian citizenship.