KABUL, Afghanistan — The Afghan government said on Saturday that it was investigating the fatal shootings by Afghan soldiers of a girl and her father in Kandahar Province, amid complaints by residents that the security forces have for years been accused of extrajudicial killings and other abuses.

The most basic details about the girl, named Naza, were conflicting. She was either 10, 13 or 17 years of age, according to different versions by at least three officials. One official said she had been out shepherding a herd of sheep near their home in Shah Wali Kot District in Kandahar when she was shot.

Khalil Ahmad Mujahid, a member of Parliament from Kandahar, said she had been in the fields near her home collecting vegetables when the soldiers had opened fire.

“The family searched for the girl the whole night, and found her body in their lands the next day,” Mr. Mujahid said.