Dawn newspaper said those killed at the Sunday night meeting of Pakistan People's Party in Sadoro Janwari village in the province's Khairpur district included six party workers and a television channel reporter. The gunmen escaped on motorcycles afterward, police said.
The attacks also injured 10 people, including three more reporters and the area administrator, Dawn said. The newspaper said the gunmen opened fire as people assembled for the public meeting.
The News International newspaper quoted a witness that one of the gunmen was holding an automatic weapon and was seen firing indiscriminately at the gathering.
Dawn quoted authorities that the shootings may have been the result of enmity between two groups from an area community.
Two of those injured were reported to be in serious condition at a local hospital.
A police official told Dawn some suspects had since been arrested and were being questioned.