Obama announces security overhaul over Detroit plot
President Obama details mistakes and actions to tackle them
US President Barack Obama has announced changes to US intelligence gathering and sharing, to prevent a recurrence of the Christmas Day plane bomb plot.
In a national address, he said the terror watch list would be boosted and security risk data better distributed.
Hundreds more air marshals will be recruited, screening at airports improved and visa rules reviewed.
Mr Obama criticised "systemic" intelligence failings over the plot, but said: "The buck stops with me."
The US failed to "connect and understand" intelligence it had prior to the failed attack on the Detroit-bound airliner, he said.
Nigerian Umar Farouk Abdulmutallab is charged with the attempted murder of 290 people, and five other counts.
Mr Abdulmutallab, 23, is to make his first appearance in federal court on Friday in Detroit for a hearing to determine if he stays in custody.
'Failure to connect'
Announcing the conclusions of a review of intelligence failures uncovered by a White House inquiry, President Obama said the US government "had the information scattered throughout the system to potentially uncover this plot and disrupt the attack".
Adam Brookes BBC News, Washington
Once again, it is the failures of the US intelligence agencies that, we are told, are to blame.
The report found that the US government did have "sufficient information" to disrupt the Christmas Day attack. But that information was scattered around different databases. It was never pulled together to present a coherent picture of the threat. A "series of human errors" occurred, apparently someone misspelled Umar Farouk Abdulmutallab's name as they entered it in a database and that is why no-one realised he had a US visa.
But these failures, said John Brennan, are different to those that preceded 9/11. Then, he said, different agencies jealously guarded information. Now, he insisted, they share. But this time, in the huge waves of information that surge through the intelligence agencies, the analysts simply failed to realise what they had.
Mr Abdulmutallab's name was on a US database of about 550,000 suspected terrorists.
However, it was not on a list that would have subjected him to additional security screening or kept him from boarding the flight from Amsterdam to Detroit.
"Rather than a failure to collect or share intelligence, this was a failure to connect and understand the intelligence that we already had," President Obama said.
He said he was ordering an immediate strengthening of the terrorist watch list, information on security risks would be distributed more widely, and analysis of that information would be improved.
Also among more than a dozen new measures are improved screening technology at US airports, the recruitment of hundreds more air marshals and a review of the issuing of US visas.
The report revealed that a misspelling of Umar Farouk Abdulmutallab's name had led the State Department to believe that he did not have a valid US visa - which he did.
Speaking after Mr Obama, US Homeland Security Secretary Janet Napolitano said hundreds of more sophisticated screening scanners would be deployed at US airports - and that foreign airports would also be encouraged to overhaul and strengthen their equipment and procedures.
While many of the barriers to sharing intelligence have been reduced, there have also been new layers of bureaucracy added to the system, correspondents say.
While he did not announce any large-scale reform, Mr Obama declared that there is a long-term challenge in making sure all the vast amount of information that is now collected by intelligence and security agencies is properly processed.
But, our correspondent adds, there are bound to be questions, not least from Mr Obama's political opponents, over whether this response is enough.
The president's remark that in the end the buck stops with him is an acknowledgement that this is being seen very much as another test of him too, our correspondent adds.
Earlier on Thursday it was reported that the alleged bomber met a radical US Muslim cleric after being recruited by al-Qaeda in London.
US TERRORIST WATCHLISTS
Terrorist Identities Datamart Environment (TIDE): intelligence on 550,000 suspected terrorists and associates
Terrorist Screening Database (TSDB): official terrorism watch list; 400,000 people which authorities have "reasonable suspicion" of having ties to terrorism
"Selectee" List: 14,000 people with suspected terrorist ties who must undergo secondary screening procedures before boarding airplanes
"No-Fly" List: 4,000 suspected terrorists who are believed to pose a direct threat to aviation or national security
Yemen's Deputy Prime Minister Rashad al-Alimi said Mr Abdulmutallab met Anwar al-Awlaki in the cleric's ancestral home province of Shabwa, having been recruited while a student at the University College London (UCL).
Mr Awlaki has been linked to an attack by a US Army major on the Fort Hood base in Texas in November, in which 13 people died.
In his remarks on Thursday, President Obama said that although the US was at war with the al-Qaeda, it did not mean America should succumb to a "siege mentality".
He said his administration would work to persuade Muslims around the world that al-Qaeda's policies and aims were bankrupt and produced only misery.
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