The CIA has launched a sweeping investigation into last week's suicide bombing at a CIA base in Afghanistan in which seven CIA employees were killed.
Investigators were exploring leads, including possible links between the bomber, a Jordanian recruited by Jordanian intelligence to try to infiltrate al Qaeda, and the network of Afghan Taliban commander Jalaluddin Haqqani, current and former U.S. intelligence officials said.
Here are some questions and answers on the Haqqani network
WHO ARE THE HAQQANIS?
The Haqqani network, headed by Jalaluddin Haqqani, is a militant group allied with the Taliban believed to be closely linked to al Qaeda and the architect of several high-profile attacks in Afghanistan.
Effective leadership of the group has passed from the ailing Jalaluddin, who is in his 70s, to his eldest son, Sirajuddin.
The senior Haqqani rose to prominence during the 1980s, receiving weapons and funds from the CIA and Saudi Arabia to fight Soviet forces occupying Afghanistan.
Haqqani has also had long-standing links with Pakistan's military Inter-Services Intelligence agency.
WHERE DO THEY STAND?
During the war against the Soviets, Jalaluddin Haqqani forged links with Osama bin Laden and still has ties with al Qaeda.
After the Taliban captured Kabul in 1996, Haqqani threw his lot in with the austere Islamists and became minister for borders and tribal areas. A month after the September 11 attacks on the United States, he visited Pakistan, raising hopes of a split in Taliban ranks. But Haqqani remained loyal to the Taliban and has not been seen in public since.
WHERE DO THEY OPERATE?
The Haqqanis are ethnic Pashtuns from the Zadran tribe in southeastern Afghanistan's Paktia province. The group maintains a power base in the Pakistani Pashtun region of North Waziristan, across the border from Afghanistan's Khost province, where the CIA base was attacked last week. The group is active across much of southeastern Afghanistan and seeks to regain full control over its traditional bases in Khost, Paktia and Paktika provinces.
The Haqqanis are thought to have introduced suicide bombing to Afghanistan. They are believed to have been behind several high-profile attacks in Afghanistan including a raid on Kabul's top hotel, an assassination attempt on President Hamid Karzai and a suicide attack on the Indian embassy.
But the Haqqani network has never been known to launch an attack on the Pakistani government or its security forces.
WHO ARE ITS ALLIES?
The Haqqani network is one of three main insurgent groups in Afghanistan, according to the U.S. military. The other two are the Quetta Shura Taliban, run by a leadership council headed by the reclusive Mullah Mohammed Omar, and the Hezb-i-Islami, run by Gulbuddin Hekmatyar, another veteran commander during the Soviet war. While coordinating efforts and sharing goals, the groups have different command structures and work under separate strategic plans, according to the U.S. military.
Sirajuddin Haqqani told Reuters last March his group was under the command of Taliban leader Omar. But U.S. officials believe the Haqqanis do not always accept Taliban authority and often act independently. He also said his group had links with al Qaeda but did not need al Qaeda support. He said his group did not need the help of foreign fighters as it had the support of the Afghan public. Security analysts point to the sophistication of Haqqani attacks as evidence of al Qaeda support.
WHAT LINKS WITH PAKISTAN?
The U.S. military says the Haqqani group draws most of its resources from Pakistan and Gulf Arab networks as well as its close ties to al Qaeda. In his telephone interview with Reuters last March, Sirajuddin Haqqani said his family had support and influence in Pakistan's Pashtun belt after being based there while fighting the Soviets. Pakistan denies supporting the Haqqani network but it has never attacked it despite mounting U.S. calls. Analysts say Pakistan sees the network as an "asset" in its bid to counter Indian influence in Afghanistan and to ensure a say in what many Pakistanis fear will be more Afghan chaos once the United States withdraws.