The GFZ German Research Centre for Geosciences said the quake hit at a depth of 10 km, measuring 6.4 on the Richter Scale. The epicentre was in the town of Petrinja, 50 km south of the Croatian capital Zagreb.
Local emergency medical services have reported that many people have been injured in the towns of Petrinja and in neighbouring Sisak.
Prime Minister Adrej Plenkovic, who rushed to Petrinja, said "There are fractures, there are concussions and some had to be operated on."
He added, "We have information that one girl was killed. We have no other information on casualties."
"The army is here to help. We will have to move some people from Petrinja because it is unsafe to be here," Plenkovic said.
A massive earthquake has just rocked Croatia, with the town of Petrinja suffering the worst damage: pic.twitter.com/smsa4cWHq8
— Seb Starcevic (@SebStarcevic) December 29, 2020
Croatia's N1 news channel quoted a Petrinja town official as saying that a 12-year old child had been killed, but gave no details.
It showed footage of rescuers in Petrinja pulling a man and a child from the debris. Both were alive.
Other footage showed a house with a roof caved in. The reporter said she did not know if anyone was inside. N1 also said a kindergarten was destroyed in the quake but there had been no children in it.
The quake was also felt in Zagreb, where people rushed onto the streets, some of which were strewn with broken roof tiles and other debris. It was also felt in Bosnia and Serbia.
Nuclear plants shut down
In neighbouring Slovenia, the STA news agency said the country's sole nuclear power plant, which is 100 km from the epicentre, was shut down as a precaution.
Hungary's Paks nuclear power plant said in a statement it had not shut down production although the earthquake had been felt there.
On Monday a magnitude 5.2 earthquake hit central Croatia, also near Petrinja. In March, an earthquake of magnitude 5.3 hit Zagreb causing one death and injuring 27 people.
Meanwhile, EU Commission President Ursula von der Leyen has said that the European Union is ready to assist Croatia with the rescue effort in the aftermath of today's quake.
After another powerful earthquake in Croatia, the 2nd in the past 2 days, I spoke with Prime Minister @AndrejPlenkovic again.
— Ursula von der Leyen (@vonderleyen) December 29, 2020
We are ready to support. I have asked @JanezLenarcic to stand ready to travel to Croatia as soon as the situation allows.
We stand with Croatia.
