How did Karachi terror attack that killed 4 Pak soldiers unfold?

An explosives-laden vehicle rammed into the headquarters of Pakistan’s Sindh Rangers in Karachi on Saturday. The assailants, belonging to Jamaat-ul-Ahrar, entered the compound, fired indiscriminately and hurled hand grenades, killing four soldiers. The attackers and security forces exchanged fire for about 90 minutes, with other units joining in and killing six terrorists and capturing one.