Three people were killed early Sunday morning, and eight were injured in a bomb blast at a cafe in the village of Idvor, northern Serbia, Novica Antonic, spokesman for the police of the city of Pancevo, told Tanjug.

He said the injured were transported to hospitals in the cities of Zrenjanin and Pancevo and to the Emergency Center in Belgrade, adding that degrees of their injuries had still not been established.

Antonic said that an investigation into motives behind the tragic event was underway.

According to Radio Television of Serbia, the tragedy occurred when the security at the cafe tried to prevent four young men from the neighboring village of Sefkerin from entering the cafe.

After an argument at the front door, S.B. (34) detonated a hand grenade. His brother (I.B.) tried to stop him, but the attempt failed. Both were killed, and the third person's identity is still unknown.

There were about 150 guests inside the cafe at time of the blast.