The girl, named Spozhmai, said her brother was affiliated with the Taliban.
“My brother Zahir and his friend Jabar forced me to wear the suicide vest,” she said.
“They also gave me extra clothes to wear after crossing the water, they brought me near the river to cross at night but when I saw the water and coldness I shouted, and said that it is cold and I can't cross the water.
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“They moved me back home and take off the vest from my body.”
She said after running away from home she surrendered herself to police.
Her father, Abdul Ghafar, now plans to take Spozhmai to live with another relative in eastern Ghazni Province after the police finish their investigation.
Commander of border police in Lashkar Gah, Colonel Hamidullah Sediqi, said it was a sad situation.
"The girl was forced by two Taliban commanders to wear the suicide vest and blow up the police base. One of the commanders is her brother,” he said.
“As you can see this is an innocent girl, she shouldn't be doing this - no one and no religion allows her to do this."
The Taliban has denied being involved.
The use of children and women bombers in Afghanistan has been relatively rare in the years since US-backed Afghan forces toppled the Taliban government.
