He promised changes in particular in the government's terrorist "watchlist" system, which came under fire for failing to identify the threat of the Christmas Day attack.
"I want our additional reviews completed this week," Obama said at the White House. "I want specific recommendations for corrective actions to fix what went wrong. I want those reforms implemented immediately so that this doesn't happen again and so that we can prevent future attacks."
On Obama's first full day back from his Hawaii vacation, he faced the challenge of spotlighting national security -- suddenly pushed to the top of his agenda -- while not looking distracted from other pressing public concerns like reducing double-digit unemployment.
The administration was on the defensive after intelligence failures allowed a Nigerian with alleged links to Yemen-based al Qaeda operatives to board a transatlantic flight from Amsterdam. The man is accused of trying to blow up the Detroit-bound plane with explosives hidden in his underwear.
U.S. spy agencies and the State Department had information about the suspect, 23-year-old Umar Farouk Abdulmutallab, but never collated the information to put him on a no-fly list.
Obama, who returned on Monday from 11 days in his home state, has been lambasted by Republicans who accuse his Democratic administration of being weak on terrorism and unable to fix intelligence gaps that have lingered since the September 11, 2001, hijacked plane attacks.
Republicans hope to score points for November elections to help challenge the Democrats' control of Congress.
"We have to do better and we will do better," Obama said as he sought to counter critics of his counterterrorism policy and grab control of the debate.