The killing of the al-Qaeda chief at a one-million dollar hideout just 120 km away from Islamabad shows that Pakistan remains a critical but "uncertain ally" in the fight against terrorism, Senator Susan Collins said.
"It's very difficult for me to understand how this huge compound could be built in a city just an hour north of the capital of Pakistan, in a city that contained military installations, including the Pakistani military academy, and that it did not arouse tremendous suspicion, especially since there were no Internet or telephone connections and the waste was incinerated and there was barbed wire all around the top of the compound," Collins said.
"So I think this tells us once again that unfortunately Pakistan at times is playing a double game, and that's very troubling to me," she told reporters here.
The Senator said US needs to need to keep the pressure on Pakistan and for that it should put "more strings attached to the tremendous amount of military aid that we give the country."
Senator Joe Lieberman said there are going to be a lot of questions raised here in the Congress about what people in the Pakistani intelligence agency particularly knew or should have known about the presence of bin Laden in Pakistan itself.
"For years, you know, the Pakistani officials have said to us he's not in Pakistan; he's in the mountains in Waziristan between Pakistan and Afghanistan."
He said, "My own experience with the Pakistanis is that this is one of the most complicated, maybe the most complicated security-intelligence relationship we have with any nation in the world, because, on the one hand, the fact is, they do give us very helpful intelligence assistance and military assistance
"(But) on the other hand, we have a lot of reason to believe that elements of their intelligence community continue to be very closely in touch with and perhaps supportive of terrorist groups that are fighting us and the Afghans in Afghanistan."
Lieberman said it will be a "real pressure" on Pakistan to prove they did not know bin Laden's presence.