The Pentagon said on Monday that the major attack on Afghanistan government buildings, military bases and foreign embassies was likely carried out by Haqqani militants who operate from sanctuaries in neighboring Pakistan.
"Initial indications are that the Haqqani network was involved in this set of attacks that occured yesterday (Sunday) in Kabul," Pentagon press secretary George Little said.
The 18-hour attack was "well-coordinated," but Afghan security forces "did a very effective job" in quelling the onslaught, Little told reporters.
The assault , one of the most serious on the capital since US-backed Afghan forces removed the Taliban from power in 2001, highlighted the ability of militants to strike the heavily guarded diplomatic zone even after more than 10 years of war.
The Afghan interior minister also said on Monday that the Pakistan-based Haqqani network was suspected to have carried out the
brazen suicide attacks
in Kabul and three other cities. Bismillah Mohammadi said that one of the militants arrested during the latest attacks on Afghanistan had told the authorities that al-Qaeda linked Haqqani network was behind the assaults.
What is the Haqqani netwok, who is the chief of the militant group and where do they operate? Let's explore the top five facts about the predominant Afghan militant group:
1. What is Haqqani network?
Named after its leader, Jalaluddin Haqqani, the so-called Haqqani network of militants, blamed for several high profile attacks against the western world, Indian embassies and government targets in Afghanistan, has emerged as a serious threat to the world.
It is often described by Pakistani officials as a predominantly Afghan militant group.
But its roots reach deep inside Pakistani territory, and speculation over its links to some powerful quarters within the Pakistani security establishment refuse to die down.
The leader of the group, Jalaluddin Haqqani, is a Jadran tribesman from Afghanistan's Paktia province. He owns properties in the neighbouring North Waziristan tribal region of Pakistan.North Waziristan was the base from where he organised raids against the former Soviet troops that occupied Afghanistan in 1980s.
American officials admit that Mr Haqqani was a prized asset of the Central Intelligence Agency (CIA) back then.
Former US Congressman Charlie Wilson, who fund-raised for the Afghan resistance, once called Jalaluddin "goodness personified".
The warrior was held in much high esteem when he visited the White House when Ronald Reagan was president.
2. Alleged links with Pakistan
He was one of the favourite commanders of Pakistan's Inter Services Intelligence (ISI) that decided which commander should get how much international funds and equipment to fight the Soviets.
Many in the West and Pakistan believe he is still an asset of the ISI, though the Pakistani military denies this.
They say the outreach of the Haqqanis would be far too limited without the material, tactical and logistical support of powerful elements in Pakistan.
But in a recent interview with the BBC, Jalaluddin Haqqani's son and its current leader, Sirajuddin Haqqani, has said there have "never been contacts by intelligence agencies of other countries (including Pakistan) which could be effective for us".
There is evidence that some top members of the Haqqani network have also been operating in the Pakistani mainland, away from their sanctuary in the Waziristan region.
3. Where do the Haqqanis operate?
The Haqqanis are ethnic Pashtuns from the Zadran tribe in southeastern Afghanistan's Paktia province.
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.
The Haqqanis, who are based in Pakistan's North Waziristan, have been heavily targeted by missiles fired from US drone aircraft.
4. Bombing campaign
A late convert to Taliban, Mr Haqqani was one of their top leaders to undertake a last official visit to Islamabad in late 2001, at about the time as the US started to bomb Afghanistan.
Mr Haqqani disappeared in Islamabad, and resurfaced several months later in the Waziristan region where he is credited with carving out the first base of militant resistance against Western forces in the most recent conflict in Afghanistan.
The Haqqani network has been blamed for a string of audacious attacks in Afghanistan and Pakistan
To this day, militants operating out of this base have inflicted more damage than any other group on Western troops in Afghanistan.
These fighters constitute the bulk of Haqqani network's fighting force.
The growing strength of Waziristan-based militants is seen as having turned the tide against the Americans in Afghanistan in recent years.
Waziristan is seen as the source of Taliban resistance in Kunar and Ningarhar provinces in the north-east of the country, and in the southern militant strongholds of Zabul, Kandahar and Helmand.
When the Americans started their bombing campaign in Afghanistan in late October 2001, thousands of Arab and Central Asian fighters started to pour into South Waziristan.
Some half-hearted attempts by the Pakistani army to check this influx led to a violent conflict in the Wana region of South Waziristan in 2002, and again in 2004.
More than 700 Pakistani soldiers were killed in those clashes.
Subsequently, Pakistanis backed down and allowed militant groups to establish deeper roots there.
By 2006, several local militant groups had emerged across the whole of South Waziristan and North Waziristan, converting the entire area into a virtual no-go zone for Pakistani officials.
January 14, 2008: Kabul Serena Hotel attack is thought to have been carried out by the network.
March, 2008: Kidnapping of British journalist Sean Langan was blamed on the network.
April 27, 2008: Assassination attempts on Hamid Karzai .
July 7, 2008: US intelligence blamed the network for 2008 Indian embassy bombing in Kabul.
November 10, 2008: The kidnapping of journalist David Rohde was blamed on Sirajuddin Haqqani.
December 30, 2009: Camp Chapman attack is thought to have been carried out by the network.
May 18, 2010: Kabul bombing was allegedly carried out by the network.
February 19, 2011: Kabul Bank in Jalalabad, Afghanistan.
June 28, 2011: According to ISAF, elements of the Haqqani network provided "material support" in the 2011 attack on the Hotel Inter-Continental in Kabul. The Taliban claimed responsibility.
September 10, 2011: A massive truck bomb exploded outside Combat Outpost Sayed Abad in Wardak province, Afghanistan, killing five Afghans, including four civilians, and wounding 77 US soldiers, 14 Afghan civilians, and three policemen. The Pentagon blamed the network for the attack.
September 12, 2011: US Ambassador Ryan Crocker blamed the Haqqani network for an attack on the US Embassy and nearby Nato bases in Kabul. The attack lasted 19 hours and resulted in the deaths of four police officers and four civilians. 17 civilians and six Nato soldiers were injured. Three coalition soldiers were killed. Eleven insurgent attackers were killed.
October 2011: Afghanistan's National Directorate of Security said that six people arrested in an alleged plot to assassinate President Karzai had ties to the Haqqani network.
April 15, 2012: The network is suspected to have carried out the brazen suicide attacks on western embassies and Parliament in Kabul.
5. What do the Haqqanis want?
The Haqqani network, according to the CTC, has played the role of “local conflict mediator over multiple decades,” and now functions as “a central diplomatic interface between the TTP and the Pakistani state when important issues need to be discussed.”
Pakistan hopes the United States will eventually welcome the participation of the Haqqanis in any Afghan peace talks. Kabul also understands the group can't be excluded.
At least three rounds of talks have so far been held in Peshawar, the capital of the north-western Khyber Pakhtunkhwa province, and in Islamabad.
This serves as an indication of the extent to which the Haqqanis can influence and shape the militant scene in Pakistan and the freedom with which they can move both within the semi-autonomous tribal areas and the Pakistani and Afghan mainlands.
Although the Haqqanis fall under the command of Taliban leader, Mullah Omar, US officials believe they do not always accept Taliban authority and can act independently.
Jalaluddin has historically shown a penchant for changing sides, as the Americans know all too well, and he may be more flexible than the hardline Siraj.
Washington is scrambling to bring stability to Afghanistan at it gradually withdraws from the country. Striking a deal with the Haqqanis may be wise while the ailing Jalaluddin might still have a say.