WASHINGTON - American leaders are putting new scrutiny on the United States relationship with Pakistan in the aftermath of Osama bin Ladens death in Abbottabad in a US military operation. Members of Congress reacted adversely after White House counterterrorism adviser John Brennan said Monday that its inconceivable that bin Laden did not have a support system in [Pakistan] that allowed him to remain there for an extended period of time. Brennan said the administration is closely talking to the Pakistanis right now about the support bin Laden received, but Congress has its own questions. Its very hard for me to understand how Pakistani, particularly the ISI, would not have known that something was going on in that compound, Sen. Dianne Feinstein, a Democrat who is the chairman Senate Intelligence Committee, said Monday. I have had a growing concern that the Pakistani government, the Pakistani military and the Pakistani intelligence community is really walking both sides of the street, and the question comes what to do about it. Pakistans choice to remain allied with the U.S. would be a much more positive choice for them long term, Ms. Feinstein said, but she added, I dont think theyve made that decision. Feinstein also said the US financial support for Pakistan should be reviewed. Our government is in fiscal distress; to make contributions to a country that isnt going to be fully supportive is a problem for many, she said. I want to think this out, talking to other members. Sen. Carl Levin, a Democrat who is the chairman Senate Armed Services Committee, said on a conference call with reporters Monday that there are a whole lot of unanswered questions here. I have some real discomfort about these facts here that seem to be so striking that it be almost impossible to conceive that the military .....and their intelligence did not know about this, the presence of this unusual compound, he said. Sen. Susan Collins. the top Republican on the Senate Homeland Security Committee, said it was very troubling to her that Pakistan appears to be playing a double game with the US. We clearly need to keep the pressure on Pakistan, and one way to do that is to put strings attached to the tremendous amount of military aid we give the country, she said. I do understand the Pakistan government is under tremendous pressure internally, but the fact is it is in Pakistans own interest to work with us to defeat the terrorist threat. Senator Joe Lieberman, an independent who is the chairman of the Homeland Security Committee, added that there will be real pressure on Pakistan to basically prove to us that they didnt know that bin Laden was there. Several leaders particularly from the Obama administration stressed the complex nature of the United States relationship with Pakistan. House Intelligence Chairman Michael Rogers, a Republican, acknowledged Monday the complexity of the US -Pakistan alliance. Liaison partnerships are always theyre never all-in propositions, he said. You have to take the service as you find it in the country of which you find it. And they the ISI and Pakistan, the government of Pakistan - have been helpful to the United States when it comes to counter-terrorism actions and investigations. Pakistan is already stressing that it did not know of bin Ladens whereabouts.