"If they continue to embrace terrorism as a part of their national strategy, we're going to have to put all options on the table including defending our troops," Senator Lindsay Graham told the Fox news in an interview.
Using a tough language against Pakistan, Graham said it is a time of choosing for Pakistan, which so far the US has been identifying as a key ally in the war against terrorism.
"I am saying that we know the Haqqani Network operates with impunity inside of Pakistan in a town called Miranshah," he said, alleging that Pakistan is terrorism itself.
He said top Pentagon officials, including Defense Secretary Leon Panetta and the Chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, are right that the ISI, the intelligence agency in Pakistan assist them directly and indirectly.
Even as the Pakistanis have done "some good things with us against al-Qaida," he said it believes that "we are leaving Afghanistan."
"They're betting the Taliban will come back. The Pakistan military lives like kings within Pakistan. A democracy in Afghanistan is a threat to Pakistani military control in their own mind," the top Senator said.
He underlined that it is "a time of choosing" for Pakistan.