GHQ Under Attack

So now our Army's Headquarter is not safe any more. If terrorists can dare to attack the high security area like that then we should be worried. Despite the heroic work of our Commandos and the praise they are getting from the media, which reminds me of the 1965's war. But who were behind this attack?
Some unknown caller, calls a news channel and says that we, Tehreek-e-Taliban are responsible for this attack. What is the authenticity of this call?
I was discussing this with my fellow blogger and he gave his points which i am writing it below.
1. Pak Army is planning for an operation in Waziristan tribal area and they were looking for a much needed excuse so thats why they planned it.
2. It may be true that Tehreek-e-Taliban is involved but doesn't it points out security breach within our government agencies.
3. By know every Pakistani knows that Blackwater, Xe and Dyncorp is operating in Pakistan. And Army is opposing Kerry Lugar Bill, so it may have been planned by America to teach a lesson to Pak Army.

Whatever it is, but it does prove that even the Headquarter of Pakistan Army is not safe from terrorist attacks. Where were ISI, MI, IB, FIA, and other intelligence agencies when these people were renting a house in Islamabad and been planning this thing from there.
We must need to get our act together, before something big happens.

What you think? Who were behind this?