Unidentified gunnies bumped off Nasiruddin Haqqani, eldest son of the group's founder, as he bought bread on the edge of Islamabad on Sunday evening.
Haqqani was the chief financier of the Haqqani bully boy network who are affiliated with Afghan Taliban and are the most feared group fighting US-led and Afghan forces in Afghanistan.
They have been blamed for spectacular attacks on Afghan government and NATO
...the North Atlantic Treaty Organization. A cautionary tale of cost-benefit analysis....
targets across Afghanistan, as well as for kidnappings and murders.
"We condemn the cowardly act of the defeated enemy and tell them that these kinds of terrorist actions will not have any negative impact on the current jihadi activities," the Taliban said in a statement.
"His death is a big loss for Islamic Emirate and all Afghanistan," it said.
Eyewitnesses described attackers on cycle of violences spraying Haqqani with automatic gunfire at a bakery in Bhara Kahu on the northeastern edge of Islamabad.
There was no immediate claim of responsibility for the killing, which came less than two weeks after a US drone strike assassinated Pak Taliban chief Hakimullah Mehsud in North
Wazoo tribal district.Washington holds the Haqqanis responsible for some of the most high-profile attacks in Afghanistan, including a 2011 siege of the US embassy and, in 2009, the deadliest attack on the CIA in 25 years.
The United States put the Haqqani network on its terror blacklist in September 2012, and the Pentagon said the group represented a "significant threat" to national security.