The US pressure resumed after the wake of Faisal Shahzad's arrest and the later US perception of his traveling to Waziristan in 2010, to seek terror training.
North Waziristan has become internationally notorious because of Faisal Shahzad for his failed Times Square bombing attempt in New York.
The notorious place has been the coaching center for the extremist militants to accomplish skills in making explosive devices. It was also the refuge of veteran Afghan Mujahideen commander, Maulvi Jalaluddin Haqqani who was the master brain behind the Taliban plots in Khost province of Afghanistan.
This area is also believed to be the hiding place for the most wanted fugitive, Osama Bin Laden and Dr Ayman Zawahiri.