The bus, operated by a private intercity service, was headed to national capital Islamabad from provincial capital Quetta, the agency said.
There were 48 passengers on board at the time of the accident, it added.
The eight injured were given first aid and then moved to a government hospital in Zhob city, about 75 km (50 miles) from the accident site in Sherani district, the agency said.
The dead were also moved to the same hospital, the agency and Sherani Deputy Commissioner Hazrat Wali said.
In a separate incident in neighbouring Afghanistan, four people were killed and 10 others were missing after a truck carrying 22 Afghan refugees from Pakistan plunged into a river along the Kabul–Jalalabad highway, military spokesperson Wahidullah Mohammadi said.
(Reporting by Saud Mehsud and Saleem Ahmed, Additional reporting by Mohammad Yunus Yawar; writing by Sakshi Dayal and Shanima Aniyeri; Editing by YP Rajesh)

Buses and trucks stand idle during a shutter-down strike in Quetta, Pakistan, 11 June 2026. The indefinite strike, organized by trade, transport and mining sector bodies, including the Balochistan Chamber of Commerce and Industry (BCCI), Anjuman-i-Tajran, the Transport Association and the Coal Mines Association, has disrupted commercial activity and transportation across the province. EPA/FAYYAZ AHMAD