“These are serious charges,” Hortefeux told France 2 television. “They are being questioned at the moment.”
The government announced tighter controls on airline passengers on Wednesday.
That followed the discovery of a number of parcel bombs, one of which was addressed to President Nicolas Sarkozy, in Greece and a parcel bomb prepared in Yemen on board an airliner heading for the US last week.
“A number of indications are leading us to be vigilant,” Hortefeux said.
French police have arrested 85 people on suspicion of plotting terror attacks since the beginning of the year and 27 of them are currently behind bars.