Five people have been arrested by the authorities in connection with the series of bomb blasts on Monday in the Pakistani port city of Karachi, IRNA news agency reported on Wednesday.
Two people were killed and over 40 injured in seven blasts that rocked the Sindh provincial capital of Karachi Monday, officials said.
No insurgent group has so far claimed responsibility for the attack.
The blasts occurred in an area mostly inhabited by ethnic Pashtoons.
Pashtoon leader Shahi Syed termed the blasts a conspiracy against the community to leave the city, where some three million Pashtoons live.
Chief minister of Sindh province, Syed Qaim Ali Shah, said a conspiracy is being hatched to destabilise the government and terrify people.
Meanwhile, intelligence experts from Islamabad have been sent to Karachi to investigate the blasts.