The first two blasts occurred near an election office of the Muttahida Qaumi Movement and a Shia mosque in Orangi Town area while the third one targeted a Pakistan People's Party (PPP) election rally in the densely populated Lyari area.
The first blast, caused by a low-intensity device, occurred near the imambargah or Shia prayer hall shortly after 9.30 pm. Minutes later, another bomb went off near an election office of the MQM in the same area.
At least two persons were killed and 25 others injured in the first two blasts while three persons were killed and 20 others, including PPP leader Adnan Baloch and several women and children, were injured in the third blast, police said.
The MQM office, which was closed at the time of the blast, suffered extensive damage. The explosion also damaged nearby homes and vehicles.
More From This Section
Police officials said the explosive device, in the third blast, was attached to a motorcycle parked in the area.
"Baloch, who was addressing the rally, has been injured in the attack while some women and children were also wounded and taken to hospital," a senior police official said.
This is the first time that a PPP election rally was targeted in Karachi.
The bombings were the latest in a series of attacks on secular parties like the MQM and Awami National Party in Karachi over the past few days. Eleven people were killed yesterday when a senior ANP leader was targeted in a bomb attack.
Two earlier bomb attacks targeting as many MQM election offices have killed at least 10 people. The MQM closed all its election offices across Sindh province following the attacks.
The banned Tehrik-e-Taliban claimed responsibility for the earlier attacks on the MQM and ANP, saying they were being targeted for their secular views and policies.