The daughter of Afghanistan’s ambassador to Pakistan was briefly kidnapped and injured, officials said.
Silsila Alikhil was held for several hours after being seized on her way home in the Pakistani capital Islamabad on Friday.
Afghanistan’s foreign ministry says she was “severely tortured” and it was lodging a complaint.
Relations between the two neighbours have long been strained.
Pakistani officials says Silsila Alikhil, who is in her 20s, was assaulted by assailants who got into a car she was travelling in and beat her up.
After her release she was treated in hospital. Condemning the “inhuman attack”, the ambassador, Najib Alikhil, said his daughter “feels better now” .
The Afghan foreign ministry expressed its “deep concern”, and urged Pakistan to guarantee the safety of diplomats and their families.
Pakistan’s foreign ministry said security of the ambassador has been tightened.
In recent weeks, ties between the two countries have been deteriorating amid rising violence in Afghanistan.
The Afghan government accuses Pakistan of providing safe haven for Taliban militants waging an insurgency across the country.
Pakistan, for its part, accuses Afghanistan of allowing militants to launch attacks from its soil.
Taliban militants have made advances across the country, seizing a series of border posts from Afghan forces.
The Taliban have moved swiftly as foreign troops step up the withdrawal of its forces from the country ahead of an 11 September deadline set by President Joe Biden.