Yesterday, a group of gunmen opened fire at the rally organised by Pakistan People's Party (PPP) at Khairpur in Sindh province which was to be addressed by MP Nafisa Shah.
DIG Ameer Shaikh told the media that the incident occurred because of enmity between two groups of the Janwari tribe. Some of the gunmen have been identified, police said.
Witnesses said a journalist and six PPP activists were among those killed in the shooting in Sardoro Janwari village.
Ten others were injured, including three reporters and an official of the local municipality.
Shah, the daughter of Sindh Chief Minister Qaim Ali Shah, told reporters that the attack was "pre-planned" and carried out with "some political motives".
The incident caused tension in Khairpur city and nearby areas. All shops and markets closed soon after the shooting.
Shah, who escaped unhurt from the incident, is a member of the National Assembly or lower house of parliament and a former mayor of Khairpur district. She is a campaigner for women's rights and a member of several parliamentary committees.