US President Barack Obama has ordered a strengthening of the US terrorist watch lists, saying the US system failed over the attempted Detroit plane attack.

In a national address, Mr Obama said the US failed to "connect and understand" intelligence it had prior to the failed Christmas Day attack.

Unveiling measures to boost security, he said "the buck stops with me".

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.

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".

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 and a review of the issuing of US visas.

The report revealed that a missspelling 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.