KABUL (AFP) - A female Afghan lawmaker kidnapped by Taleban militants was the victim of a plot hatched by her brother, the country's intelligence agency said on Wednesday.

Ms Fariba Ahmadi Kakar, one of 69 female MPs in the 249-seat Lower House, was taken at gunpoint in August and held for three weeks before being released, reportedly in exchange for six Taleban prisoners.

The National Directorate of Security (NDS) said that her brother Noor Ahmad had been arrested on charges of being a key accomplice behind the kidnapping, which attracted global headlines.

"The NDS investigation concluded that two people including Noor Ahmad, brother of MP Kakar, had plotted the kidnapping with a Taleban commander," the spy agency said in a statement.

It also released a video of Ms Kakar's brother making a tearful confession.

"Money and some family issues may have been the motive," NDS spokesman General Farid, who only uses one name, told AFP.

Ms Kakar was returning to Kabul from her constituency in Kandahar when she was taken hostage at gunpoint along with her three children, who were released soon after being abducted.

"I am even braver than before," she said in an interview after her release.

"I will defend Afghanistan, especially the women, until the last drop of my blood."

Women in public life have often been targeted by Islamist militants, with two senior female police officers recently killed in Helmand province.