Just days before a historic briefing in Congress, top secret documents suggest Pakistan "routinely received classified briefings" on drone strikes inside its borders.
It is claimed top secret documents and diplomatic memos reveal Pakistan has known about and endorsed US drone strikes for years and that Pakistani officials routinely received classified briefings on casualty counts.
The number of civilians killed in Pakistan by US drones is estimated to be between 407 and 926. There have been 376 known strikes targeting militants since 2004, mostly in Pakistan's mountainous and remote Waziristan region.
The Washington Post, which obtained the CIA files, wrote: "The files describe dozens of drone attacks in Pakistan's tribal region and include maps as well as before-and-after aerial photos."
It said markings on the documents indicate that many of them were prepared by the CIA's Counterterrorism Center specifically to be shared with Pakistan's government.
Earlier this week President Obama and Pakistani Prime Minister Nawaz Sharif met in the US and pledged to cooperate on security issues. Bombing raids by US drones have stoked widespread resentment in Pakistan.
Sharif said he raised the issue during the leaders' two-hour meeting, "emphasising the need for an end to such strikes." However, Obama made no mention of drones following the discussion.
The revelations by the Washington Post come ahead of a historic hearing in the US.
On Tuesday (29 October) two children, who were injured in a drone attack in north west Pakistan which killed their grandmother, will appear along with their father at a briefing in the US Congress.
Rafiq ur Rehman, a primary school teacher in North Waziristan, and his children Nabila, 9, and Zubair, 13, will attend the briefing called by Congressman Alan Grayson. Mr Rehman's 67-year-old mother died in a drone strike one year ago.
Their lawyer Shahzad Akbar told Channel 4 News: "Rafiq and his children do not trust the US, their mother was killed in front of their eyes by the US operated drones."
Of the CIA documents, he said: "We have not just suspected but alleged a similar thing in our Peshawar high court litigation that Pakistan is not just complicit in giving tacit consent - but actively has been playing a role."
And he is sceptical about Sharif's plea to Obama.
"I think PM Sharif really wants drones to stop but lacks initiative.
"He asks Obama to stop the drones and invites Obama to visit Pakistan to eat Qeema (mince meat dish) and daal (lentils) in Pakistan at the same time. This doesn't come over as a leader of one nation asking another nation to stop killing its citizens."
Congressman Grayson said: "I'm looking forward to hearing from the drone strike victims,"
"When it comes to national security matters like drone strikes, it's important that we hear not only from the proponents of these attacks, but also from the victims."
This will be the first time that members of Congress have heard testimony direct from civilian victims of the CIA’s covert drone campaign.