An advert warning Egyptians to be on the lookout for spies has been aired on state and satellite TV channels.
The advert warns that foreigners acting in a friendly manner and asking questions could be spies.
It also advises people not to talk with strangers and avoid sharing information about the country with foreigners.
Information regarding marriage and unemployment are to be avoided, the advert says.
Xenophobia has grown in Egypt since the January 25 Revolution. The Supreme Council of the Armed Forces has alleged several times that foreign hands have incited protests across the country.