The army has been fighting against militants in FATA region + Waziristan for 2+ years now.....

Those groups you are talking about operate in Kashmir and do attacks on the other side of the LOC.

There is no group that operates there that are allowed to be there. When U.S or any government comes out and presents concrete evidence I will believe it.

The foreign policy of the country is run by the army not the federal government. The federal government and political parties have forever used various tactics to get control from the army away. This is nothing new. When Pakistan says that isn't correct, Pakistan is run by multiple players vying for power.... it is not a proper run democratic system, so please understand this.

The army assisted another party to overthrow the existing leading party to put in place another once a few years ago and it failed.... the politicans blame the army for not fighting Taliban enough. This is nothing new.

When the foreign world says Pakistan they think of 1 entity that is doing all this.... there are various players with their own interests, their own reasons for doing things. Understand this the country is very complex in how it is run currently.

Did Pakistan support Afghan Taliban back in the day... yes. Does it support them right now? No evidence suggests that they have since the army operation started in the nothern areas. Afghanistan government is pissed off that when the army started clearing Waziristan all the taliban / militants ran across the border and are conducting operations there and extending their support networks there. That is not Pakistan's problem, you have NATO go do something it yourself.