The transport security administration said its officers would patrol all public areas. Until now security has been concentrated on the search areas, through which all passengers have to pass, and armed troops- usually members of the National Guard - have kept an eye on the hand-baggage checks. There has been no attempt to match the machine-gun patrols at the main British airports.
Three people were killed, including the gunman Hesham Hedayet, when he began firing at the El Al ticket desk at Los Angeles airport on Thursday. The agency admitted that if the attack had involved a less terrorism-aware airline than El Al the situation would have been far worse.
"This incident, even if isolated and regardless of motive, emphasises that we cannot be complacent," its statement said.
It has not said how many officers will be used, where or when, but it has confirmed that many of them will work under cover, and that to begin with local policemen will be used.
They will be stationed in the public areas near ticket desks, where there is no restriction on access, and "airside" - in the area beyond the security checkpoints, where there has been almost no visible police presence until now.
The agency is currently taking on thousands of employees as part of the "federalisation" process by which it is replacing the private companies previously responsible for inspection.
Congress has imposed a November 19 deadline for ensuring that all screeners are federal employees who have themselves been screened.
