A 25-year-old man brought a hand grenade from a bedroom during the party last night and handed it to another man, authorities said.

The grenade exploded, killing one man and injuring four others.

“The investigation team and a police bomb disposal unit determined that the explosion was caused by an M75 hand grenade,” police said.

A minor was among the injured.

Tatijana Sipalo Ilic, director of Knin Hospital, told local media that the injured “have multiple injuries” but are currently stable.

Knin mayor Marijo Cacic said it was a great tragedy for the town.

A criminal investigation is ongoing into the blast.

Knin, where this explosion occurred, was one of the key battlegrounds during the wars in the 1990s after the breakup of Yugoslavia.

Leftover weapons and explosives still pose a risk to communities there today.

The Croatian police have been running a national campaign for years called “Less Weapons, Fewer Tragedies” aimed at encouraging citizens to surrender illegal weapons and ammunition to reduce violence and weapon-related accidents.

Police in Knin have taken in some 5,091 weapons, ammunition and explosive devices since the beginning of the year.

They have collected 33 firearms, 4,986 rounds of ammunition, 32 explosive devices and 18.4kg of explosives.

Some 60 firearms, 999 rounds of ammunition, 134 pyrotechnic devices and 1.5kg of explosives have also been confiscated.