BUJUMBURA, June 13 (Xinhua) -- Unidentified persons Tuesday night blasted a grenade in a house in Cibitoke province, northwestern Burundi, killing one person and injuring six others, a local official told Xinhua on Wednesday.

At 7:49 p.m. local time, unknown people broke into a house at Murwi village in Murwi district, exploding a grenade in the dining room where the house occupants were eating their dinner, said Salvator Niyobuhungiro, adviser of the Murwi district administrator.

A 13-year-old girl died on the spot and six others were injured, said Niyobuhungiro.

According to him, five persons were seriously injured and were evacuated to hospital.

When people came to rescue the victims, the attackers had already run away, Niyobuhungiro added.

Three suspects have been arrested for further investigations, he said, adding that land conflicts are suspected to be at the origin of the grenade explosion.

Another grenade attack happened Tuesday night at a neighborhood in northern Bujumbura, capital city of Burundi, but did not cause casualties, spokesman of the security ministry Pierre Nkurikiye said Wednesday.