Pakistan continues to be a "tremendously duplicitous partner," according to Bob Corker, chairman of the U.S. Senate Foreign Relations Committee.
Corker, a Republican, said during a Senate hearing on U.S. policy in Afghanistan on September 15 that Pakistan was the "greatest threat to American soldiers [in Afghanistan] and certainly the greatest threat to the Afghan military and civilians."
Corker said Islamabad was "working against" U.S. interests by supporting the Haqqani Network, a Pakistani-based militant group that has been blamed for some of the deadliest attacks against U.S. and Afghan forces in Afghanistan.
Richard Olson, the U.S. Special Representative for Afghanistan and Pakistan, said Islamabad had not done enough to tackle the Haqqani Network and the Taliban.
"We continue to urge Pakistan to take robust action against the Haqqani and against the Taliban and I think there are indications that they have taken some action, but I don't think it will be fair to say those actions were definitive," Olson told the Senate hearing on September 15.
Afghan and U.S. officials have long blamed Pakistan for supporting the Afghan insurgency, a charge rejected by Islamabad.