The top U.S. military officer made headlines this week when he said a particularly ruthless Islamic militant group killing Americans in Afghanistan "acts as a veritable arm" of the intelligence service of America's nominal ally Pakistan.
In one of the many ironies of the war on terror, the leader of the militant group, the so-called Haqqani network, was once a trusted ally of the CIA in the fight against the Soviets.
Nowadays, the Haqqani network maintains close ties to both al-Qaida and the Taliban. The Haqqanis, who are credited with introducing suicide bombing to Afghanistan, wield an estimated 10,000 fighters and are considered the most dangerous insurgent group in the decade-long war.
The U.S. has fired scores of missiles over the last two years into the Pakistani tribal region of North Waziristan, which the Haqqanis control and use as a safe haven in which they provide shelter to al-Qaida figures.
Despite the drone strikes, the Haqqanis have not only thrived, they are accused of carrying out an increasing number of high-profile attacks in Kabul and elsewhere in Afghanistan. Such assaults have heightened the sense that Afghan and foreign forces are failing in their mission to stabilize the country.
U.S. Joint Chiefs of Staff Chairman Adm. Mike Mullen accused the Haqqani network of staging an attack against the U.S. Embassy in Kabul last week and a truck bombing that wounded 77 American soldiers days earlier. He claimed Pakistan's most powerful spy agency, the ISI, helped the group.
"With ISI support, Haqqani operatives planned and conducted that truck bomb attack, as well as the assault on our embassy," Mullen told the Senate Armed Services Committee on Thursday. He also said the United States had credible information that Haqqani extremists, with help from the Pakistani intelligence agency, were responsible for the June 28 attack on the Inter-Continental Hotel in Kabul and other small but effective assaults.
On Friday, Mullen's spokesman said his boss decided to lay out accusations against the ISI after information about the linkage became more available in recent weeks.
"It's been a very busy summer for the Haqqani network and it's gotten worse," said Capt. John Kirby. "Their activity has become more brazen, more aggressive, more lethal, and the information has become more available, that these attacks have been supported or even encouraged by the ISI."
Pakistan's army chief dismissed the allegations that his spy agency helped Afghan militants attack the U.S. Embassy in Kabul, saying the charges were baseless and part of a public "blame game" detrimental to peace in Afghanistan.
Gen. Ashfaq Pervez Kayani, who trained in the United States, said in a terse statement Friday that the allegations were "very unfortunate and not based on facts."
Kayani's statement appeared to imply that Pakistan's contacts with the Haqqani network were part of efforts to bring it to the negotiating table. The United States, Kabul and European countries all agree that a peace deal will be needed to end the war, though not all agree on whether the Haqqanis should be included.
The statement said that "on the specific question of contacts with Haqqanis ... Admiral Mullen knows fully well which ... countries are in contact with the Haqqanis. Singling out Pakistan is neither fair nor productive."
Many analysts believe the ISI's support for the Haqqanis has continued since the Soviet war, driven by an attempt to promote Pakistan's interests in Afghanistan and counter the influence of archenemy India.
Afghan and U.S. intelligence officials claim the ISI provided Haqqani fighters with intelligence necessary to carry out a car bombing at the Indian Embassy in Kabul in 2008, said a report last year by the U.S.-based New America Foundation report.
ISI support for the Haqqanis mainly involves this type of intelligence sharing and also providing safe haven in North Waziristan, said the report. Pakistan has refused to launch an operation against the Haqqani network despite repeated demands by the U.S., which has provided the country with billions of dollars of military and economic aid.
In return, the Haqqanis have tried to persuade allies like al-Qaida and the Pakistani Taliban to focus their attacks against Afghan and foreign forces in Afghanistan rather than the Pakistani state, said the New America Foundation report.
It's unclear how much success this effort has had since the Pakistani Taliban in particular have continued to carry out attacks through the country that have killed thousands of civilians and members of the Pakistani security forces.
The group's founder, Jalaluddin Haqqani, received extensive support from U.S. and Pakistani intelligence agencies to fight the Soviet Union after its 1979 invasion of Afghanistan. Haqqani is now believed to be in his 60s or older and has handed day-to-day operations of the group over to his son, Sirajuddin.
The elder Haqqani developed close ties to al-Qaida chief Osama bin Laden during the Soviet war when both of them spent months together on the front lines, according to the New America Foundation report.
The network's ties to al-Qaida and other foreign militant groups have remained strong, one of the reasons why it has become such a potent force in Afghanistan, said the report. The group has used foreign fighters to provide training and to carry out dramatic suicide attacks in Kabul, it said.
The elder Haqqani initially opposed the Taliban when they rose up in the 1990s following the Soviet withdrawal. But he eventually became an ally, helped the group seize control of Afghanistan and became a minister in the Taliban government.
The Haqqani network has pledged allegiance to Taliban leader Mullah Omar, but the group largely operates independently from its base in North Waziristan, where the Haqqanis and other fighters fled following the U.S. invasion of Afghanistan in 2001.
The group has used its bases in North Waziristan to send fighters into the Haqqanis' homeland in eastern Afghanistan and farther north to Kabul.
The network is believed to be comprised of several hundred core members and thousands of fighters with varying degrees of affiliation and loyalty, said a recent report by West Point's Combating Terrorism Center.
The Haqqanis largely fund their operations with donations from wealthy individuals, usually from Persian Gulf states, said a recent report by the U.S.-based Institute for the Study of War.
The elder Haqqani speaks fluent Arabic and one of his two wives is from the United Arab Emirates, assets that have helped him raise money in the Gulf, said another report from the institute.
The group also raises money by taxing local elders and companies in criminal enterprises such as chromite and timber smuggling as well as kidnapping and extortion.
One of the reasons the U.S. has had difficulty countering the network is because the Americans have been more focused on the Taliban's spiritual heartland in southern Afghanistan rather than the east, said the report. The U.S. has attempted to address this in the past couple years by stepping up attacks against Haqqani fighters using special forces troops in Afghanistan and unmanned drones in North Waziristan.
The Haqqani network has been responsible for many of the attacks in eastern Afghanistan, and the younger son has been working to expand the group's operational base beyond the family's traditional homeland, the Institute for the Study of War quoted U.S. military officials as saying. He has also strengthened ties with foreign militant groups and adopted more brutal tactics, including beheading women and other indiscriminate killing, they said.