The bomber was apparently targeting a police official who was inside the shop, said Ghulam Dastagir Azad, the governor of Nimroz province. The explosion in the provincial capital killed the official and five civilians, he said.
Nimroz Police Chief Gen. Jabar Pardeli confirmed the figures. Four shops were also destroyed in the blast.
Separately Friday, three soldiers with NATO's International Security Assistance Force were killed in the south, the force said in a statement. A spokesman said they were killed in a bomb explosion in Zabul province. He spoke on condition of anonymity, citing policy. NATO did not release the troops' nationalities; its policy is to wait for governments to provide those details.
The assault followed a coalition strike on a bomb-making network in Zabul on Thursday in which the U.S. military said five militants were killed.
The troops were pursuing a Taliban militant known to have directed roadside bomb attacks along the country's major highway, the military said in a statement. During the strike on his compound, they came under fire from those inside. The statement says the militants refused calls to surrender and the coalition forces killed five armed militants and captured three suspects in the ensuing clash.
The statement did not say if the targeted militant was among the dead.