"Most of Petrinja’s centre, according to preliminary estimates, is in the ‘red zone,’ meaning it is not livable", Andrej Plenkovic told reporters.
The earthquake struck the central European country at around noon, collapsing buildings and killing a girl. Twenty other people were injured. A search-and-rescue operation is underway.
The prime minister said the tremor was felt across Croatia. Neighbouring countries also reported the jolts.
Hundreds of people left homeless in Petrinja will be sheltered in barracks, with another hundred to move into a hotel, Plenkovic said. He promised that no one will be left out in the cold.