Travellers from nine South Asian, African and Middle Eastern nations are likely to face increased scrutiny at Phnom Penh’s airport security, according to a new release from Wikileaks.

The leaked 2011 classified document from the US Central Intelligence Agency advises undercover spies in transit on how to avoid enhanced, secondary security screenings that could compromise identities.

‘‘Travelers from specific countries arriving at international airports are more likely to receive heightened scrutiny, and referral to secondary screening, than other travelers,” the advisory says.

At Phnom Penh International Airport, passport carriers from Afghanistan, Algeria, Bangladesh, Iraq, Iran, Pakistan, Saudi Arabia, Sudan and Sri Lanka can trigger terrorism alerts.

Chief of investigations at the Immigration Office Uk Hai Sela said he had “no idea” about heightened security checks or travel flags for some nationalities at the airport.