PESHAWAR: The Tehrik-i-Taliban Jundullah group on Thursday claimed responsibility for the attack on the compound of Pakistan's Inter Services Intelligence (ISI) in Sukkur.

Spokesperson for the proscribed militant group, Ahmed Marwat, told Dawn.com from an undisclosed location that the attack was carried out in retaliation to the recent killing of their comrade, Waliur Rehman, and drone strikes carried in the region.

He further claimed that "the militant organisation had sent four suicide bombers to target the ISI office because the Pakistani Army and ISI are working in connivance with the US."

An apparent suicide bomber first blew himself up in front of a police building on Wednesday and then a second suicide bomber detonated an explosive-filled car outside the ISI office in Sukkur.

The terrorists had seized control of one government building, sparking a shoot-out between the militants and security forces in the high-security Barrage Colony area.

At least nine people were killed, including five attackers and four agency officials in the attack.