Arms firms that provide core military components for drones deployed by the US to conduct covert strikes in violation of international law bought access to NATO’s summit in Wales last week, a British human rights charity says.

The defense companies concerned doled out up to £300,000 to ‘exhibit’ their military wares at the conference in Newport. Among the firms present were General Dynamics, Raytheon, Lockheed Martin and MBDA, according to a British government press release.

General Dynamics manufacture Hellfire missiles utilized in most US drone strikes, while Raytheon make the targeting system for the Reaper drone deployed by the CIA and other actors to conduct strikes across the globe. Lockheed Martin operates as a contractor to provide select support services for both the Reaper and Predator, and MBDA is a European company that manufactures the unmanned aerial vehicle (UAV) Brimstone - a variant of the Hellfire missile.

US drone strikes have roused widespread international criticism. Critics emphasize attacks carried out in foreign states with which the US is not at war are in violation of international and US law. This is particularly evident in the case of Yemen and Pakistan, they caution.

Although US drone strikes have culminated in hundreds of civilian casualties, they are subject to little oversight, according to Reprieve. President Barack Obama has refused to formally acknowledge the ooccurrence of many US drone attacks.

Reprieve’s Legal Director Kat Craig emphasized it’s “deeply worrying” that a group of firms who potentially profit most from this breach of international law were able to buy access into a global summit like NATO.

“It is unacceptable that the US’ drone campaign, and the UK’s support for it, has been allowed to remain in the shadows for so long”, he added.

“President Obama must be far more open about it - as must his European allies, especially the UK and Germany, about the support they provide.”

Craig suggested the drone manufacturers’ presence at NATO signaled their inherent capacity to buy political influence “behind closed doors,” highlighting the opaque, illicit and legally questionable nature of much of the global arms trade.