Al-Qaeda and Ansarul Aseer, militant wing of Tehreek-e-Taliban Pakistan (TTP), were behind the jailbreak plan, security sources said.
The target of the militants was to set 125 terrorists of TTP and other banned outfits free from the Karachi central jail, the sources said.
The security sources further said that some jail officials, directly or indirectly, were part of this conspiracy, adding that financial assistance of approximately Rs 90 million for this plan was transferred from Afghanistan.
The terrorists used modern technologies for breaking into the jail and also used the satellite to search the entrance route into the barracks, the sources said, adding that with the help of GPS a line was drawn for digging the tunnel from the house.
The security sources further revealed that the next target of the terrorists was Sukkur and Hyderabad jails.