The blast occurred inside a house.

Two men and a woman were killed on Thursday night when the blast rocked their house in the Gulzar Aka area of the provincial capital, the Khost police chief told Pajhwok Afghan News.

Brig. Gen. Akhtar Mohammad Noorzai told Afghanistan-based news agency police team had reached the area for investigations.

He said nothing about the nature of the explosion.

No group has claimed responsibility for the attack so far.