Wikileaks has released two classified documents instructing CIA operatives how best to circumvent global security systems in international airports, including those of the EU, while on undercover missions.

The first of the documents, dated September 2011, advises undercover operatives how to act during a secondary airport screening. Secondary screenings pose a risk to an agent’s cover by focusing “significant scrutiny” on an operative via thorough searches and detailed questioning.

The manual stresses the importance of having a "consistent, well-rehearsed, and plausible cover," in addition to cultivating a fake online presence to throw interrogators off track.

Meanwhile, the second document, dated January 2012, presents a detailed overview of EU Schengen Border Control procedures.

RELEASE: Classified CIA documents show how to infiltrate the world's airports https://t.co/2pnmvfD0Cnpic.twitter.com/aoT1jx8eXM — WikiLeaks (@wikileaks) December 21, 2014

The overview outlines the various electronic security measures, including the Schengen Information System (SIS) and the European fingerprint database EURODAC, used by border control and the dangers these measures may pose to agents on clandestine missions.

WikiLeaks' сhief editor Julian Assange explains that these documents show that “under the Obama administration the CIA is still intent on infiltrating European Union borders and conducting clandestine operations in EU member states."

The document also demonstrates the CIA’s increasing concern over the risks to operatives' assumed identities posed by biometric databases—the very same systems the US pushed for after 9/11.

On Friday, WikiLeaks released a CIA report suggesting that though targeted killing programs, including drone strikes, may be effective in some cases, there is also a risk that the programs may backfire. For example, targeted strikes may prompt local populations to sympathize with insurgents or further radicalize remaining militants.

READ MORE: Leaked CIA report says targeted killing programs could backfire