|Admiral Michael Mullen linked Pakistan's intelligence agency to an attack on the US embassy in Kabul [AFP]
The Haqqani network is a "veritable arm" of Pakistan's intelligence agency, the top US military officer has said, adding that the agency supported the group in its attack last week on the US embassy and NATO headquarters in Kabul.
"The Haqqani network ... acts as a veritable arm of Pakistan's Inter-Services Intelligence Agency," Admiral Michael Mullen, chairman of the US Joint Chiefs of Staff Committee, said on Thursday in prepared remarks to the US Senate Armed Services Committee.
The Haqqani network, which is distinct from the Afghan Taliban, is a member of the allied factions that are fighting the United States and NATO troops in Afghanistan.
"With ISI support, Haqqani operatives planned and conducted [a September 11] truck bomb attack, as well as the assault on our embassy," Mullen said. "We also have credible intelligence that they were behind the June 28 attack against the Inter-Continental Hotel in Kabul and a host of other smaller but effective operations."
Pakistan has denied the allegations.
Such high-profile attacks have been a blow to the US plan to withdraw its troops from Afghanistan, which is due to begin this year and end in 2014.
Also speaking at the hearing, Leon Panetta, the US defence secretary, said that these sorts of attacks were a sign of "weakness" on the part of fighters in Afghanistan.
"Overall, we judge this change in tactics to be a result of a shift in momentum in our favour and a sign of weakness in the insurgency," Panetta told the committee.
Just two days after the assassination of Burhanuddin Rabbani, the former Afghan president who was playing a role in mediating with the Taliban, Panetta said that as "the Taliban lost control of territory last year they shifted away from large attacks on our forces to greater reliance on headline-grabbing attacks".
Panetta said that the best signal that the US could send was that they would continue to fight the Taliban, and that this would convince them to negotiate a peaceful settlement.
Mullen, who is to step down this month from his post as head of the Joint Chiefs of Staff, agreed with Panetta's assessment. He said that while high-profile attacks were "serious and significant in shaping perceptions ... they do not represent a sea change in the odds of military success".
Panetta claimed that security was improving across Afghanistan, particularly in areas where the US has increased troop numbers, though he did not go into specifics.
"While overall violence in Afghanistan is trending down, and down substantially in areas where we concentrated our surge, we must be more effective in stopping these [high-profile] attacks and limiting the ability of insurgents to create perceptions of decreasing security," he said.
He said the US military is "working with our Afghan counterparts to discuss with them how we can provide better protection against these attacks. But the bottom line is that we can't let these sporadic events deter us from the progress that we've made".
The comments on Pakistan's alleged links to the Haqqani group come after a series of tough statements from US officials on the subject, but were the toughest yet from Mullen.
"In choosing to use violent extremism as an instrument of policy, the government of Pakistan - and most especially the Pakistani Army and ISI [intelligence service], jeopardises not only the prospect of our strategic
partnership, but also Pakistan's opportunity to be a respected nation with legitimate regional influence," Mullen said.
"By exporting violence, they have eroded their internal security and their position in the region. They have undermined their international credibility and threatened their economic well-being," Mullen said.
Panetta echoed that sentiment, and when questioned by Senator Carl Levin, the chairman of the committee, on what the US could do in addition to applying diplomatic pressure, he declined to share "operational details" on what could be done.
"I don't think [Pakistani leaders] would be surprised by the actions we might or might not take," he said.
Yet Mullen stressed that Pakistan had a crucial role to play in the achievement of US objectives in the region.
"A flawed and difficult relationship [with Pakistan] is better than no relationship at all," he said, adding praise for Pakistani authorities for having targeted al-Qaeda leaders in the country.
Senator John McCain, the ranking member of the committee, said that while Panetta and Mullen may be continuing efforts to achieve US objectives with regards to Pakistan through negotiations, it would be an "uphill battle" to convince the US Congress to continue its current levels of aid and funding to the country.
In an interview with the Reuters news agency on Thursday, Rehman Malik, the Pakistani interior minister, denied US allegations of Pakistani state support for the Haqqani network or the attack on the US embassy in Kabul.
"If you say that it is ISI involved in that attack, I categorically deny it. We have no such policy to attack or aid
attack through Pakistani forces or through any Pakistani assistance," Malik said.
Malik conceded that some Haqqani fighters were present in Pakistan's North Waziristan area, but that Pakistan lacked the resources to "trace them".
"We are fighting a common enemy but unfortunately not with a common strategy. Instead of a blame game we have to sit together. We are not part of the terrorism, we are part of the solution."
He also said Pakistan would not allow any US incursion into Pakistan.
"The Pakistan nation will not allow the boots on our ground, never. Our government is already cooperating with the US ... but they also must respect our sovereignty," he said.
"One thing has to be understood, if you remember just a little over a week ago Sirajuddin Haqqani, who is supposed to be the commander of the Haqqani network, categorically stated that his military operations were from inside Afghan territory," reported Al Jazeera's Kamal Hyder from Chilas, northern Pakistan.
"Recently Pakistan has come under heavy attack in Chitral ... at the same time, what the Pakistanis have been saying is that the Afghan army [has] failed and that there are attacks happening inside Pakistan and that the Americans are not doing anything about it.
"What is happening at the moment is a real test for Islamabad and Washington, and it seems that the relationship is not getting any better."