General Nahim Baluch, the deputy director of Afghanistan's intelligence service, said that the ringleader - whom he did not name - and several other suspects confessed to their role in the January 18 attack that paralysed the Afghan capital and left 12 people dead, including seven militants.
``All of them have links with al Qaeda,' Baluch said of the suspects. Afghan officials have previously said that the Haqqani network, a Pakistan-based Taliban faction with close ties to al Qaeda, was behind the assault. Baluch said Sunday that al Qaeda was increasingly directing complex attacks carried out by its close partners. Analysts and US counterterrorism officials have said al Qaeda leaders have deepened and solidified their relationship with the Taliban and other home-grown militant groups that operate along the porous Afghan-Pakistan border.