The two ill-fated buses collided in Salgiran area, near Muree,a resort, before plunging into the ravine, Geo News quoted police as saying.
Rescue workers recovered 15 bodies from the gorge, officials said. The exact number of the dead and injured, however, was yet to be ascertained.
The injured included 20 men and six women. Nine of them were critically wounded, media reports said citing hospital officials.