Pakistan for years secretly approved of US drone attacks on its territory despite public denunciations, The Washington Post reported on Wednesday, citing secret documents.
The report of Islamabad's involvement came even as Prime Minister Nawaz Sharif visited the White House and urged an end to the attacks, which are widely unpopular with the Pakistani public and have raised much controversy in recent days.
Pakistani support for drone attacks has long been widely suspected, although strikes reported by The Washington Post involved several years up to 2011, before a slowdown in strikes and Sharif's election in May.
The newspaper said that top-secret documents and Pakistani diplomatic memos showed that the Central Intelligence Agency had drafted documents to share information on drone attacks with Pakistan.
At least 65 drone strikes were marked for discussion with Pakistan, including through briefings at its embassy in Washington and in materials sent physically to senior officials in Islamabad.
In one case in 2010, a document describes hitting a location "at the request of your government''. Another file referred to a joint effort at picking targets.
The article - co-written by Bob Woodward, one of the two journalists who broke the Watergate scandal in the 1970s - said the documents also showed that the United States raised concerns that extremists were linked to Pakistan's powerful intelligence service.
In one incident, then secretary of state Hillary Clinton confronted Pakistan about cellphones and written materials from bodies of militants that showed links to Pakistan's Inter-Services Intelligence agency (ISI).
In turn, a Pakistani memo gave the names of 36 US citizens believed to be CIA agents and urged the embassy in Washington not to issue visas to them, the newspaper said.
The report came a day after Amnesty International said that the United States may have broken international law by killing civilians with drones (See: Top US law schools had blasted drone strikes before Amnesty).