HONOLULU, Hawaii (AFP) - President Barack Obama planned to spend New Year's Eve Thursday plowing through initial probes into the botched bombing of a US plane, after slamming "systemic" intelligence failures.

The top US intelligence official Dennis Blair meanwhile delivered a sobering warning that future attacks would be harder to stop, as Al-Qaeda deepens its knowledge of US defense systems and how to get past them.

Obama, angered by how narrowly tragedy was averted in a country still scarred by the September 11, 2001 attacks, said he was expecting to receive two reports on reviews he demanded into the Christmas Day attack later in the day.

After reviewing them over the weekend, the president plans to meet heads of intelligence agencies and government departments next week to discuss the findings after returning from vacation in Hawaii.

"On Tuesday, in Washington, I will meet personally with relevant agency heads to discuss our ongoing reviews as well as security enhancements and intelligence-sharing improvements in our homeland security and counter terrorism operations," Obama said in statement.

The president spoke earlier Thursday about the two reviews with Homeland Security Secretary Janet Napolitano and his top counterterrorism advisor John Brennan.

Detroit flight plot may prove boon for security firms

Obama ordered the reviews after revealing that intelligence about Umar Farouk Abdulmutallab, the alleged bomber of the Northwest jet, had not been shared between agencies and he was not a "no fly" list.

"Intelligence itself, and the collection thereof is always going to be difficult and is not always going to result in complete information and he understands that," a senior US official said on condition of anonymity.

"But by the same token, when we do have good information ... the failure to share that information is not going to be tolerated."

Obama has been receiving regular updates on the probes and issues related to the attack on paper and online and officials and US agencies were working overtime to plug gaps in the US aviation security system.

"It's a heck of a Happy New Year," the official said.

Blair, the director of national intelligence, told his staff in a letter on Thursday that the fight against Al-Qaeda, which has claimed the Christmas Day attack, was about to get even tougher.

"What concerns me most now is not only stopping the types of attacks of the past, but also anticipating and stopping the different, more cunning attacks of the future," he said.

"Al-Qaeda and its affiliate organizations, as well as individual suicide terrorists, have observed our defenses and are designing future attacks to circumvent them.

"These attacks will be even harder to uncover, interpret, and stop."

Blair also referenced Obama's scathing assessment of intelligence failures ahead of the attack.

"This is a tough message for us to receive. But we have received it, and now we must move forward and respond as a team," he said.

An official traveling with Obama in Hawaii said that he did not see the message before it was released.

In another development, Napolitano said she would send senior deputies to meet officials in charge of airport security in Asia, Europe, Africa, the Middle East and South America.

"We are looking not only at our own processes but also beyond our borders to ensure effective aviation security measures are in place for US-bound flights," Napolitano said.

Nigeria said Thursday that Abdulmutallab had started his journey in Ghana and transited through Lagos, before connecting with the Northwest flight in Amsterdam.

He is accused of trying to blow up the plane as it approached Detroit by setting off explosives stitched into his underwear. The attempt failed when he was stopped by passengers.

According to the Washington Post and The New York Times, electronic communications intercepted from Yemen by the National Security Agency had warned that an unidentified Nigerian was training for an Al-Qaeda mission.

Other communications spoke of a plans for a Christmas Day attack.

Experts agreed that security agencies had failed despite still being on alert after the 2001 attacks which killed almost 3,000 people and propelled the United States into ongoing conflicts in Afghanistan and Iraq.

"The intelligence failed and physical security failed, eight years into the war on terrorism. With all the investment poured into this, you would expect to have a system that works more efficiently," Bruce Hoffman, from Georgetown University, told AFP.