A 2011 internal CIA manual that instructs operatives on how to get through some of the world's toughest airport security screenings without blowing their cover was released by Wikileaks this week.

The guide was produced by the CIA's Checkpoint Identity and Travel Intelligence Program, which Wikileaks says was previously unknown and focuses on "providing tailored identity and travel intelligence" to personnel. It was distributed to those in the CIA, the Executive Branch, and other US agencies that would need it, according to Wikileaks.

The document was published at the height of global airport travel for the Christmas holiday, and exposes specific details about many security tactics at European and Middle Eastern airports.

In Iran, for example, travelers who are found to have photos of protests on them are often subjected to a secondary, intensive screening of all of their personal belongings, particularly their computers. In Cairo, security officials tend to send passengers for extra screening if they have an advanced scientific degree — say if the individual is a humanitarian or human rights worker, or are American-Egyptian.

The guide also offers broad stroke advice to those traveling under aliases on how to avoid being detected while moving through airports. Operatives are instructed to avoid looking nervous. Shaking hands, rapid breathing, cold sweats, and lack of eye contact can all be detected as nervous behavior by trained security officials.

One airport in the Republic of Mauritius actually uses a camera to zoom in on arriving passengers' faces as they pick up their bags to try and detect any wayward or nervous behavior. Budapest uses one-way mirrors to look for the same.

Other red flags for initial screeners are one-way tickets, tickets that were purchased the same day as the flight, tickets booked by government travel agencies or that include a government or military discount, and lack of appropriate baggage to match the cover story, whether a business trip or tourist trip.

Ben Gurion Airport in Israel will send military age males with backpacks to secondary screening, regardless of where they're from or where they say they're going, according to the document.

Once passengers are sent to a secondary screening room they can undergo hours of intense questioning — or just a quick nudge for a bribe.

A detailed account of Ben Gurion Airport's secondary screening room suggests it was provided by someone with intimate knowledge of the space, which includes "trace-detection equipment for explosive residue, tools for dismantling passengers' personal items for inspection, particularly items unfamiliar to security officers, and a disrobing area, divided by privacy curtains, to conduct strip searches of individuals if necessary."

Everything that screeners come across must match the cover story, the report emphasizes, down to the "pocket litter" the passenger is carrying around. A mobile phone or iPod that requires subscriptions or an account name can be a dead giveaway if registered to the person's real name.

The manual concludes with a story about an experienced CIA traveler going through a European airport and being chosen for a secondary screening, likely because of "overly casual dress inconsistent with being a diplomatic passport holder."

In the secondary screening room, the traveler's bags tested positive for explosives. The officer said he had been at counterterrorism training in Washington, DC, which eventually, despite skepticism by security officials, worked at getting him boarded onto a flight.

But Wikileaks, in a press release accompanying the report, drew attention to this anecdote.

"Although he was eventually allowed to continue, this example begs the question: if the training that supposedly explained the explosives was only a cover story, what was a CIA officer really doing passing through an EU airport with traces of explosives on him, and why was he allowed to continue?"

"The CIA has carried out kidnappings from European Union states, including Italy and Sweden, during the Bush administration," WikiLeaks' Editor-in-Chief Julian Assange said in the press release. "These manuals show that under the Obama administration the CIA is still intent on infiltrating European Union borders and conducting clandestine operations in EU member states."

A second document released at the same time shows the CIA's concern for increased security measures at EU airports that could begin next year, including fingerprint screening and biometric screening, which would make it difficult for operatives to use aliases to travel.

Follow Colleen Curry on Twitter: @CurryColleen