"The police reject any doubts about being in the service of any political party," Interior Ministry spokesman Zlatko Mehun told Hina, adding that those were "Mesic's political assessments".
Earlier in the day, speaking at a Zagreb open-air market as part of his election campaign, Mesic accused the police of being "increasingly in the service of one party because they sanctioned the removal of a poster from a place where no posters are allowed".
Mesic said he did not know who had removed a poster of HDZ candidate Jadranka Kosor from a tree in Duga Resa, about 60 kilometres southwest of Zagreb, during his visit to the town on Thursday.
Mehun said that the police had set up a special team to monitor police activities in the field during the election campaign and to coordinate the activities of all election teams and all presidential candidates in order to ensure that police officers performed their duties professionally.
"The police have so far received no complaints about the behaviour and work of police officers," Mehun said.
Mehun said that the police had acted in accordance with the law when they filed misdemeanour charges against a member of Mesic's security team, Perica Martinovic, after he was caught tearing down Kosor's posters.