A top US intelligence official has promised action after sharp criticism from President Barack Obama over a failed airliner bomb plot.
Director of National Intelligence Dennis Blair said the intelligence community had to boost efforts to prevent new types of attacks.
Mr Obama had earlier told senior officials that the failure to anticipate the attack was a "screw-up".
The alleged bomber is accused of trying to bring down an airliner over Detroit.
Mr Obama said US intelligence officials had known that Al-Qaeda in the Arabian Peninsula (AQAP), which claimed responsibility for the plot, had been planning an attack against America.
He also said they knew the group had been working with an individual - now known to be Umar Farouk Abdulmutallab, a 23-year-old Nigerian charged over the plot.
The intelligence community had failed to "connect the dots", Mr Obama said in a statement, adding: "That's not acceptable, and I will not tolerate it."
'We got it'
Mr Abdulmutallab's name was on a US database of about 550,000 suspected terrorists, but not on a list that would have subjected him to additional security screening or kept him from boarding the flight from Amsterdam to Detroit.
Mr Blair reacted by acknowledging the failure of the intelligence community to catch the suspect.
"The intelligence community received the president's message today - we got it, and we are moving forward to meet the new challenges," he said.
He added that intelligence officials had made "considerable progress" in collection and analysis of information and in improving collaboration, although they needed to strengthen their ability to stop "new tactics".
Mr Blair's position was created in the wake of the 11 September 2001 attacks in the US, amid efforts to improve intelligence co-ordination.
The White House said before Tuesday's security meeting that Mr Obama was standing by three of his top security officials, including Mr Blair.
But the BBC's Richard Lister in Washington says that given Mr Obama's comments, it seems likely that there will be some kind of shake-up and that heads will roll.
Mr Obama spoke on Tuesday after being briefed on security reviews ordered after Mr Abdulmutallab's arrest.
According to the White House, he used stronger language in the closed-door meeting with top security officials.
"This was a screw-up that could have been disastrous," it quoted the president as telling them. "We dodged a bullet but just barely."
Those who attended the meeting included Secretary of State Hillary Clinton, Defence Secretary Robert Gates, Homeland Security Secretary Janet Napolitano, CIA Director Leon Panetta and FBI Director Robert Mueller.
Enhanced airport screening and a review of the US watch-list system were ordered after the 25 December attempted attack.
Since the incident, officials have moved dozens of names on to "watch" and "no-fly" lists, as they seek to overhaul security.
Those on the watch-list are subject to extra security checks, while those on the no-fly list are not allowed to board flights to the US.
The suspect began his journey in Lagos, Nigeria, and changed planes at Schiphol airport in Amsterdam, in the Netherlands.
Nigeria, Somalia and Yemen were among the 14 countries singled out by Washington for enhanced security measures for travellers, introduced on Monday.
Countries considered by the US to be sponsors of terrorism - Cuba, Iran, Sudan and Syria - were also included.
The move sparked objections by some of the states. Cuba and Nigeria said they had protested to US diplomats.
Mr Abdulmutallab was allegedly trained in Yemen - a country that has come under increased scrutiny from the US since his arrest.
The US suspended the repatriation of Yemeni prisoners from its Guantanamo Bay detention centre in the wake of the plot, though Mr Obama reiterated that he would push on with his plan eventually to close the prison.
The US re-opened its embassy in Yemen on Tuesday, following what it called successful counter-terrorism operations by government security forces on Monday north of the capital.
Yemeni authorities have tightened security measures at Sanaa's airport, as well as around several other embassies.