Another seven have been wounded in the shooting, of which five came in with severe injuries, according to authorities.
An assailant entered an elderly care home in the central Croatian town of Daruvar, killing at least four people, authorities said.
Police said they were informed after 10 am Monday that a man using firearms killed and wounded several people at the nursing home.
The suspect fled the scene, but the police soon caught him in a cafe in downtown Daruvar.
“The person suspected for the crime has been apprehended,” the Bjelovar-Bilogora County Police said in a statement.
The number of those killed might be at least five, domestic outlets claim. Another seven have been wounded in the shooting, of which five came in with severe injuries, according to the head of the hospital in nearby Pakrac.
“Our teams are still on site, and the priority is to provide the necessary help to everyone,” the head of the regional emergency services, Nenad Mrzlečki, told the domestic press. “Only after that will we know the exact casualties.”
The mass shooting in Daruvar has shocked the Adriatic nation of some 3.8 million.
“We are appalled by the murder of five people in the Home for the Elderly in Daruvar,” Croatian Prime Minister Andrej Plenković wrote on X. “We express our condolences to the families of the victims and hope for the recovery of the wounded.”
Plenković is set to make a public address at 2 pm CET, while Deputy PM Davor Božinović is said to be on his way to Daruvar together with health and labour ministers.
Authorities are investigating the motive behind the attack. The gunman is believed to be a veteran of Croatia’s war of independence in the 1990s, however.
Daruvar is a spa town and municipality in Slavonia, with a population of about 8,500 people.