The gunman, who was identified as a former war veteran, has been arrested, according to local sources.
The attack occurred in the city of Daruvar, located east of Zagreb. Croatian media outlets reported that the gunman entered the nursing home and opened fire, killing his mother and four other residents.
Those injured in the shooting were transported to local hospitals for treatment.
Prime Minister Andrej Plenkovic expressed his condolences to the victims' families, calling the attack "appalling."
An investigation is underway by local police. No further details concerning the motive for the shooting have been released. (ILKHA)