Police used batons to disperse hundreds of people on Saturday after they attacked the Afghan consulate here to protest the killing of 16 nationals by Afghan security forces.
Chanting slogans against Afghan President Hamid Karzai, the protesters hurled stones and tore off a picture of the Afghan leader displayed at the gate of the consulate building in this south-western city of Quetta.
Police moved quickly and forced some 450 demonstrators to disperse before they could enter the consulate premises, witnesses said. The crowd chanted "Down with Karzai and Death to Afghanistan," and left after the police action.
Pakistan has already protested to Afghanistan over the killing of 16 men who were shot dead on Tuesday in Afghanistan's border district of Spin Boldak.
Afghanistan said the victims were Taleban militants who crossed the frontier from Pakistan, but Islamabad insisted they were Pakistani tribesmen who were on their way to celebrate the Afghan New Year.
The incident came amid an ongoing dispute between the two countries over security along their rugged border.
Pakistani foreign ministry said the victims were arrested in Kabul at an unknown time and then handcuffed, tied up and brought to Spin Boldak before being killed.
Thousands of tribesmen attended the funerals of eight of the dead in the Pakistani border town of Chaman, opposite Spin Boldak. Three others were buried in Quetta.