Ryan Crocker, at a news conference in Kabul, called the network "a group of killers, pure and simple," Voice of America reported. He said Secretary of State Hillary Clinton, during a meeting this week with her Pakistani counterpart, Hina Rabbani Khar, urged Pakistan to eliminate sanctuaries along the border with Afghanistan for the network and other insurgent groups.
"She said that action has to be taken against these groups and against the safe havens that they currently enjoy because they are a threat to Afghanistan, they are a threat to the United States and the international community, and they are a threat to Pakistan itself," Crocker said.
The Taliban claimed responsibility for attacks Sunday on Kabul and three other locations, saying they demonstrated their group could carry the fight into areas believed to be secure. But observers said they appeared to have the hallmarks of a Haqqani attack.
The relationship between Pakistan and the United States has been frayed by drone strikes, especially one that killed 24 Pakistani soldiers, and the raid on Osama bin Laden's compound last year, which was carried out without notifying the Pakistani government in advance.
Rustam Shah Mohmand, a former Pakistani ambassador to Kabul, has accused the United States of using charges about the Haqqani Network to justify the drone program.
"From the American point of view, the sanctuaries of the Haqqani network exist here in Pakistan," he said. "If that is true and that is verified, so what have the drones been doing? I mean they have been dropping, they have been striking those targets for the last five, six years."