Pakistani police say unknown gunmen pulled 20 Shi'a off buses near Naran Valley in northern Pakistan and shot them dead.
The attack targeting Shi'a was the second such incident in the area in six months.
The bus was traveling from the city of Rawalpindi to the northern town of Gilgit, in a mostly Shi'ite area.
It was ambushed in the hills of Babusar Top, some 160 kilometers north of the capital, Islamabad.
Based on reporting by AFP, AP, and RFE/RL's Radio Mashaal