The U.S. routinely briefs Pakistan officials in secret on drone strikes in the country, according to a Washington Post report from Bob Woodward and Greg Miller out Wednesday evening. The report details a previously-reported implicit endorsement of the program from Pakistan, comes hours after Pakistan's Prime Minister Nawaz Sharif called for an end to U.S. drone strikes in the country. Woodward and Miller write that the government's endorsement of the program is one of the more poorly kept national security secrets" in both countries. 

The National Journal reported earlier on Wednesday that the governments of George W. Bush and Pervez Musharraf set up a secret agreement years ago giving Pakistan knowledge and approval of the CIA's drone program, based on interviews with U.S. and Pakistani officials. The protocol is still in effect today but viewed warily by Pakistan's current civilian government. The Post report adds more details to that story, and is based on a series of documents going back to 2007 through 2011. Some of the files appear to be specifically prepared by the CIA's Counterterrorism Center for sharing with Pakistan's government. Here's more from the Post

The files expose the explicit nature of a secret arrangement struck between the two countries at a time when neither was willing to publicly acknowledge the existence of the CIA drone program. The documents detailed at least 65 strikes in Pakistan and were described as “talking points” for CIA briefings, which occurred with such regularity that they became a matter of diplomatic routine. The drone documents are marked “top secret” but cleared for release to Pakistan.

In addition to those briefings, the memos indicate that Pakistan could be putting in requests for specific targets. One CIA document refers to a "a joint CIA-ISI targeting effort," while another references hitting a location "at the request of your government."

The files also document some tensions between the two countries, specifically over reports of a Pakistani intelligence agency's militant ties. In response to U.S. confrontation over those reports, the Post explains, Pakistan apparently tried to prevent its embassy in Washington from issuing visas to CIA agents. 

Earlier studies of the CIA's drone use hinted at Pakistan's complicated relationship to the program. From 2004 to 2007, the government claimed responsibility for U.S. strikes against some targets in its own country, and have publicly praised some militant deaths due to the operations. But as a Stanford/NYU report on the CIA's drone program shows, that public support has all but vanished since the Obama administration escalated drone use in the country. By 2013, two years after the last document reviewed by the Post, a Pew poll found that just 5 percent of Pakistanis approved of  American drone use, while 68 percent disapproved. 

The documents also provide a very detailed accounting of the secretive drone strike program, and there's another interesting finding on that note: the history of the program outlined in the CIA's files actually corresponds pretty closely to those of independent organizations tracking U.S. drone strikes. However: the CIA doesn't seem to think that its strikes, despite the circumstantial evidence on which they're sometimes based, have killed virtually any civilians: 

One table estimates that as many as 152 “combatants” were killed during the first six months of 2011 and 26 injured. Lengthy columns with spaces to record civilian deaths or injuries contain nothing but zeroes.

As the Post points out, that goes against independent assessments of drone strike civilian deaths. A report from Amnesty International released earlier this week, for instance, argues that U.S. officials responsible for the program in Pakistan could stand trial for war crimes. And the Bureau of Investigative Journalism believes that 2,525-3,613 people have died in drone strikes in the country.