The Afghan government accounted for 46 percent of violence against journalists in the first half of the year.
The majority of the victims were killed by anti-government forces, says the report.
Ghani has come under mounting public criticism for spiraling insecurity.
The vehicle was reportedly a water tanker stuffed with more than 1,500 kilogrammes of explosives.
Abdul Hasib is said to have been killed last month in a targeted raid by special forces.
America has about 8,400 troops in Afghanistan. Most belong to a NATO mission to train and advise Afghan partner forces fighting the Taliban
Iran has been sheltering a million registered Afghans for almost four decades.
Afghan police, already stretched on multiple insurgent battlefronts, are struggling to rein in kidnapping rings.
At least one person was killed and 35 others wounded in the carnage.
Bloodied corpses of the policemen were strewn around the checkpoint, many of them shot from close range.
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