The UK and Australian governments may be complicit in the U.S.’s covert drone campaign in countries outside of recognized war zones, a new analysis of British intelligence documents published Wednesday reveals.

Previously undisclosed files from the UK’s Government Communications Headquarters (GCHQ) agency, provided to the Guardian by NSA whistleblower Edward Snowden and analyzed by leading human rights lawyer Jemima Stratford, “raised questions about British complicity in US strikes outside recognized war zones and demonstrated the need for the government to come clean about the UK’s role” in the U.S.’s secret targeted killing program, particularly in the case of an airstrike which killed two men in Yemen on March 30, 2012.

The documents, which the Guardian shared with the New York Times, also reveal the existence of a program codenamed “Overhead”, operated jointly by the U.S., UK, and Australian governments, which supported the 2012 strike and helped the U.S. develop target-tracking capabilities in both Yemen and Pakistan, crucial elements in the drone program. “Overhead began as a US operation but has operated for decades as a partnership with GCHQ and, more recently, Australian intelligence,” write the Guardian‘s Alice Ross and James Ball.

Also revealed are a series of internal GCHQ newsletters, titled Comet News, which updated the agency’s staff on Overhead operations over a two-year period. The memos show how the NSA turned its focus on Yemen as a “surveillance priority,” and, for the first time, names one of the men killed in the 2012 strike—Khalid Usama, a doctor who the agencies believed was helping surgically implant explosives into al Qaeda operatives.

Ross and Ball explain:

In the two years of memos seen by the Guardian, this was the only specific strike detailed, raising questions as to why GCHQ’s team decided to notify staff about this particular strike among hundreds.

The Guardian asked GCHQ whether this was because UK personnel or bases were involved in the operation. The agency declined to comment, and offered no explanation as to why British staff were briefed on this particular strike.

Other memos refer to one of the British intelligence gathering teams involved in Overhead, codenamed “Widowmaker.” The team, based in Pakistan, was tasked to “discover communications intelligence gaps in support of the global war on terror,” Ross and Ball write. “Illustrating the close links between the UK, US and Australian intelligence services, Widowmaker personnel are based at Menwith Hill in the north of England, in Denver, Colorado, and in Alice Springs in Australia’s Northern Territory.”

Stratford, who analyzed the documents for the Guardian, said, “Assuming that the documents which I have seen are genuine, in my view they raise questions about the extent to which UK officials may have had knowledge of, or helped to facilitate, certain US drone strikes which were not carried out in the context of an international armed conflict.”

“These documents underline why greater transparency as to UK official policies would help to ensure legality from a domestic and international law perspective,” Stratford added.

Ross and Ball continue:

Click Here: creed perfume sale

The incident is one of more than 500 covert drone strikes and other attacks launched by the CIA and US special forces since 2002 in Pakistan, Yemen and Somalia – which are not internationally recognised battlefields.

The GCHQ documents also suggest the UK was working to build similar location-tracking capabilities in Pakistan, the country that has seen the majority of covert strikes, to support military operations “in-theatre”.

Despite the revelations in the documents, the British government has refused to acknowledge its role in the drone strikes. Again from the reporting:

The Guardian contacted GCHQ with the information contained in this article, and asked a series of questions on the extent of intelligence sharing with the US in connection with targeted killing, and the legal framework for any such activities. The agency declined to comment on specifics.

The Guardian asked Downing Street why it refused to clarify any UK role in US drone strikes. A government spokesperson said: “It is the longstanding policy of successive UK governments not to comment on intelligence operations. We expect all states concerned to act in accordance with international law and take all feasible precautions to avoid civilian casualties when conducting any form of military or counter-terrorist operations.”

Human rights organizations have long called for the U.S. to cease its covert drone campaigns. An investigation by the Open Society Justice Foundation, published in April, found that the target killing program in Yemen not only fails to conform to protocols established by U.S. President Barack Obama, but also further destabilizes the region and increases anti-American sentiment overseas.

 In its reporting, the New York Times noted:

Last week offered two more examples of the uncertain outcomes of airstrikes. A prominent Algerian terrorist, widely reported dead in a Pentagon strike by F-15s, appears to still be alive. And only several days after a strike in Yemen did American officials learn that an attack had killed the leader of Al Qaeda in the Arabian Peninsula, who was also the No. 2 leader of Al Qaeda’s global terror network.

Opposition to the drone campaign also flared in April after the Obama administration confirmed that a secret airstrike had killed two Western hostages. Critics said the deaths highlighted how the program often relies on faulty intelligence.

Jameel Jaffer, legal director at the ACLU, said the drone strikes “make clear that there is a significant gap between the relatively stringent standards the government says it’s using and the standards that are actually being used.”