WASHINGTON — The Obama administration will announce today a new screening system for flights to the United States under which passengers who fit an intelligence profile of potential terrorists will be searched before boarding their flight, a senior administration official said.

The procedures, which have been approved by President Barack Obama, are aimed at preventing another terror attack like the one attempted by Umar Farouk Abdulmutallab, the Nigerian suspected of ties to al-Qaida who tried to blow up an airliner Christmas Day with a bomb hidden in his underwear, the official said.

In the wake of that attempt, the administration began mandatory screening of airline passengers from 14 high-risk countries.

Under the new system, passengers on flights from all countries could be subject to special screening before boarding if they have personal characteristics that match the latest intelligence information, the official said.

“We believe it is a much more effective system,” that is “tailored to optimize our ability to interdict would-be terrorists,” said the senior official, who described the plan.

Even U.S. citizens traveling to the United States from abroad who matched the characteristics would be subject to special screening, the official said.

Administration officials said the system would not amount to improper profiling because relying on specific and frequently updated intelligence and broadening the number of countries covered beyond the current 14 provided for greater fairness than the current system.

The new plan is designed to catch terrorists about whom the U.S. may know bits of information but not full names or other identifying data. In many cases, the U.S. might learn of a possible attack by someone about whom it has only fragmentary information – a partial name, certain facial features or details about recent travel.

Such information will be forwarded to airlines and foreign governments by the Department of Homeland Security and will be used to guide them in deciding which travelers to subject to special screening,.

In the case of Abdulmutallab, U.S. intelligence had received communication intercepts months before the Christmas Day attempt about a suspected plot involving a Nigerian as well as a partial name. The breakdown came because intelligence officials failed to match that information with a tip they received from Abdulmutallab’s father.