Insurgent violence in Afghanistan this year will likely double that of 2005 and will continue next year, the US military's top intelligence official told Congress on Wednesday.
General Michael Maples, director of the US Defence Intelligence Agency, said insurgents had expanded their abilities and operations even while incurring serious combat losses.
"Despite having absorbed heavy combat losses in 2006, the insurgency has strengthened its capabilities and influence with its core base of Pashtun communities," he told the Senate Armed Services Committee.
"Violence this year is likely to be twice as high as the violence level seen in 2005 ... In 2007, insurgents are likely to sustain their use of more visible, aggressive and lethal tactics," he said.
Maples said the insurgents aimed to undermine the international community's support for Afghanistan military and reconstruction operations, and to demonstrate the Kabul government's weakness.
The head of the Central Intelligence Agency, General Michael Hayden, in his testimony emphasised the need to continue supporting the Afghan government of President Hamid Karzai.
"Kabul needs help because it lacks capacity, not because it lacks political will or lacks support," Hayden said. "President Karzai understands this and recognises his government's responsibility."
Citing a recent conversation with the US ambassador in Kabul, Ron Neuman, Hayden said "the effort would take a long time -- in my view, at least a decade -- and cost many billions of dollars. I would add that the Afghan government won't be able to do it alone."