WASHINGTON - Evidence gathered since the assault that killed Osama bin Laden reveals top leadership in the Pakistani government did not know the Al-Qaeda leader was hiding in their country, top Pentagon officials said. I have seen no evidence at all that the senior leadership knew, Secretary of Defence Robert Gates said in a Wednesday afternoon press conference. In fact, Ive seen some evidence to the contrary. Gates said he has a supposition that someone in Pakistan knew bin Ladens whereabouts, but it may take time to find out who. Somebody had to know, he said. But we have no idea, and we have no proof and we have no evidence. Since the May 1 raid on bin Ladens compound in Abbottabad, members of Congress have called for cutting off government aid sent to Pakistan, a move Gates cautioned against. I never fired anybody because they didnt know about a problem If they didnt know, its hard to hold them accountable for it, the defence secretary said about the Pakistani government. Gates said the US government is only providing anti-terrorism reimbursements to the Pakistani military. These reimbursements face strict scrutiny and can only be claimed by filing a specific form. When we reimburse them, it is for a specific thing they have done with respect to the war against terror in Pakistan or in support of what we are trying to do, he said. Gates said that while he understands Capitol Hills frustration with Congress, the governments relationship with Pakistan remains critical and should not be abandoned altogether. That said, I think we have to proceed with some caution, he said. We do have significant interests in Pakistan. Chairman of the Joint Chiefs of Staff Adm Mike Mullen, who sat alongside Gates, said bin Ladens capture has instilled a desire in the Pakistani government to pursue suspected terrorists more strongly, as their nation is being used as a safe haven. This is certainly not the first time this issue has been raised with the Pakistani leadership And I do think they understand this is a priority, Mullen said. Gates said Pakistan had already been burdened for their oversight. If I were in Pakistani shoes, Id have already paid the price, he said. Id be humiliated. Agencies add: Gates and Mullen also advised against cutting off aid to Pakistan for its failure to go after militant leaders, saying Washington had important interests at stake and that Islamabad had already been humiliated by the raid. I think we have to proceed with some caution, Gates said. My own view is we need to continue the assistance that we have provided that benefits the Pakistani people, he said. The Pentagon chief, in his first press conference since bin Laden was killed on May 2, argued against punishing Pakistan by suspending aid as Islamabad had suffered a blow as a result of the covert raid. If I were in Pakistani shoes, Ive already paid a price. Ive been humiliated, Ive been shown the Americans can come in here and do this with impunity, he said. He said he shared the frustration felt by US lawmakers towards Pakistan but stressed that President Barack Obamas administration could not make allegations without evidence. Its hard to go to them with an accusation when we have no proof that anybody knew. Mullen said it would take time to learn who may have known about bin Laden in Pakistan as intelligence agencies are still poring over a large amount of material found at the Al-Qaeda leaders compound. Both military leaders said government officials had to stop leaking out details of the raid that killed Osama bin Laden or otherwise risk future operations by special forces. My concern is that there were too many people in too many places talking too much about this operation, Gates told reporters. Im very concerned about this, because we want to retain the capability to carry out these kinds of operations in the future. And when so much detail is available, it makes that both more difficult and riskier, said Gates, a former CIA director. Mullen, agreed with Gates, expressing frustration that some officials and retired officers had discussed details of the raid and the special forces that carried it out. We have, from my perspective, gotten to a point where we are close to jeopardising this precious capability that we have, and we cant afford to do that, Mullen told the same Pentagon press conference. It is time to stop talking. And we have talked far too much about this, he said. Information about the US raid and what was found at the Al-Qaeda leaders hideout in Pakistan have steadily trickled out in media reports since bin Laden was killed by a team of Navy SEAL commandos on May 2. Gates said security was being increased for the Navy SEAL team after members told him they were concerned about the safety of their families due to publicity surrounding the operation. All I will say is that we have been taking a close look at that and we will do whatever is necessary, he said. Meanwhile, US Senate Majority Leader Harry Reid has played down talk of cutting aid to Pakistan in the wake of Osama bin Ladens death, saying now was the time to 'withhold judgment, not money. Right now, were at a very difficult time. We need to see if we can improve the relationship, the Democratic lawmaker told reporters, stressing: This isnt the time to start flexing our muscles. Lawmakers of both major US parties have pushed for re-evaluating Washingtons aid to Islamabad after elite US commandos found the elusive Al-Qaeda in a fortified compound not far from Islamabad in a town with a military academy. But others have warned that cutting off, freezing, or attaching new conditions to US assistance - which has totalled roughly $20 billion since 2001 - would damage a troubled but critical relationship in the war on terrorism. I think this is the time that we withhold judgment. Before any moneys going to be asked to be sent to Pakistan, there will be hearings; there will be discussions in the White House. There will be diplomatic activities, said Reid. I dont think we need at this stage to talk about what were going to do, because that decision doesnt have to be made right now, said the senator. Reid told reporters that Democratic Senator John Kerry had briefed his colleagues behind closed doors on his just-finished whirlwind trip to Afghanistan and Pakistan, where he expressed Washingtons frustration about Islamabads uneven efforts to battle extremists. Reid cited good things that we have already seen happen as a result of the visit by Senator Kerry - notably the return of the tail of a helicopter US Navy SEALs were forced to destroy during the May 2 raid. There are some things that are beginning to help, and we need to work together. Its very important that we continue a good relationship with Pakistan, said Reid. Meanwhile, US senators have urged Secretary of State Hillary Clinton and Defence Secretary Robert Gates to make sure Pakistan is doing its utmost to battle extremists before disbursing more US security aid. The lawmakers, all Democrats, wrote Clinton and Gates a letter Tuesday in the wake of the raid in which elite US commandos found and killed Al-Qaeda chief Osama bin Laden in a Pakistani military town not far from the countrys capital. We recognize the strategic importance of Pakistan, wrote the group, which include Senate Intelligence Committee Chairwoman Dianne Feinstein and Senate Finance Committee Chairman Max Baucus. However, we cannot overlook the logical conclusion of recent events, which is to question whether the Pakistani security establishment is ardently working to prevent terrorist groups from operating on Pakistani soil, they said. The senators called for reviewing Pakistans efforts to end its support for extremist groups, prevent Al-Qaeda, the Taliban and others from operating on Pakistani soil, and bolster its counter-terrorism and anti money-laundering laws. We believe that conducting this assessment will be crucial for the Congress to determine whether to provide the full range of security assistance, they said in the letter. Finding bin Laden in a Pakistani town indicates, at a minimum, a lack of commitment by the Pakistan to aggressive cooperation with the United States, the senators said. This is particularly concerning as the Congress again considers increasing security assistance to Pakistan, they said. Meanwhile, the United States is striving to have an understanding with Pakistan on way forward that continues anti-militant progress in the region and answers a lot of the concerns that both sides have at this point, Secretary of State Hillary Clinton said. She indicated intensive diplomatic engagement between the two countries in the weeks ahead as they seek to salvage the relationship - seen critical to US success in Afghanistan - and overcome tensions arising in the wake of Osama bin Ladens discovery in Abbottabad and the May 2 US unilateral action to take Al-Qaeda leader out. We are working very hard to have an understanding with our counterparts in Pakistan about the best way forward, Clinton told reporters Tuesday after meeting New Zealands foreign minister. In her media interaction at the State Department, the top American diplomat would not comment specifically on any issue between the two countries.