Kasi was shot and killed early on Monday morning while on his way to the main court complex in Quetta.
The explosion occurred as mourners, mostly lawyers and journalists, gathered to accompany the body of Bilal Anwar Kasi, a prominent lawyer, who was shot and killed in the city earlier on Monday, an eyewitness said.
More than 50 mourners were entering the emergency department of the hospital, accompanying Kasi's body, when the bomb went off, Faridullah, a journalist who was at the scene, told Reuters.
Baluchistan's Home Minister Bugti said at least 10 people were killed and 30 wounded, though some media reported higher casualties.
Television news channel Geo reported that at least 15 people were killed, and more than 20 wounded.
Kasi was shot and killed early on Monday morning while on his way to the main court complex in Quetta, Geo reported.
Targeted killings have become increasingly common in Quetta, the capital of a province that has seen rising violence linked to a separatist insurgency as well as sectarian tensions and rising crime.
The motive behind Monday's attacks, however, was unclear.