A spokesman for provincial police department, Hazrat Hussain Mashriqwal, said the party was on a bird hunting expedition and was carrying weapons at the time of the strike late Friday.
A NATO spokesman told Khaama Press authorities were aware the strike had taken place but could not confirm any casualties.
Two Afghan police officers were killed and nine other people were injured in the explosion of a roadside bomb in northern Faryab province, officials said. The injured included other police officers and civilians, Khaama Press reported Friday.
The incident occurred when explosives packed on a bicycle detonated as the officers, all members of the border protection force, were on patrol, said Abdul Jamil Sediqi, chief of the Qaisar district.
No group has claimed responsibility for the blast.