An al-Qaida affiliate in Yemen apparently ordered the Christmas Day plot against a U.S. airliner, training and arming the 23-year-old Nigerian man accused in the failed bombing, President Barack Obama said yesterday.

“;This is not the first time this group has targeted us,”; Obama said, reporting on some of the findings of an administration review into how intelligence agencies failed to prevent Umar Farouk Abdulmutallab from boarding Detroit-bound Northwest Flight 253.

In his most direct public language to date, Obama described the path through Yemen of Abdulmutallab. He also emphasized that the United States would continue its partnerships with friendly countries—citing Yemen in particular—to fight terrorists and extremist groups.

The U.S. plans to more than double its counterterrorism aid to the impoverished, fragmented Arab nation in the coming year to support Yemen's campaign against al-Qaida.

Obama's homeland security team has been piecing together just how Abdulmutallab was able to get on the plane. Officials have described flaws in the system and by those executing the strategy and have delivered a preliminary assessment.

A top counterterrorism official said yesterday that al-Qaida and other extremists are working to test U.S. defenses and launch an attack on American soil.

The failed attempt against the plane “;is the starkest of reminders of the insidious terrorist threats we face,”; said Michael Leiter, director of the National Counterterrorism Center. “;We know with absolute certainty that al-Qaida and those who support its ideology continue to refine their methods to test our defenses and pursue an attack on the homeland.”;

The center, part of the Office of the Director of National Intelligence, draws experts from the CIA, FBI, Pentagon and other agencies who try to ensure that clues about potential attacks are not missed.

A senior administration official had said the U.S. increasingly was confident of a link between Abdulmutallab and an al-Qaida affiliate, but Obama's statement was the strongest connection between the two. The official said regular updates from the White House Situation Room and from his homeland security advisers gave Obama enough confidence to use his radio address—typically focused on domestic priorities—to communicate a stark message about Abdulmutallab.

“;We know that he traveled to Yemen, a country grappling with crushing poverty and deadly insurgencies. It appears that he joined an affiliate of al-Qaida, and that this group—al-Qaida in the Arabian Peninsula—trained him, equipped him with those explosives and directed him to attack that plane headed for America,”; the president said in his weekly radio and Internet address. It was released by the White House during Obama's vacation in Hawaii.

Officials have said Abdulmutallab's father warned the U.S. Embassy in Nigeria that his son had drifted into extremism in the al-Qaida hotbed of Yemen. Abdulmutallab's threat was only partially digested by the U.S. security apparatus and not linked with a visa history showing the young man could fly to the U.S.

Obama has ordered a thorough look at the shortcomings that permitted the plot, which failed not because of U.S. actions but because the would-be attacker was unable to ignite an explosive device. He has summoned homeland security officials to meet with him in the White House Situation Room on Tuesday.

Intelligence officials prepared for what was looking to be uncomfortable hearings before Congress about miscommunication among anti-terror agencies and sweeping changes expected under Obama's watch.

Obama noted that in recent years, the al-Qaida affiliate in Yemen has bombed government facilities there as well as Western hotels, restaurants and embassies. An attack on the U.S. Embassy in 2008 killed one American.

“;So, as president, I've made it a priority to strengthen our partnership with the Yemeni government—training and equipping their security forces, sharing intelligence and working with them to strike al-Qaida terrorists,”; he said.

The U.S. provided Yemen $67 million in training and support under the Pentagon's counterterrorism program last year. Only Pakistan got more, with some $112 million.

The U.S. general who oversees the wars in Iraq and Afghanistan told reporters in Baghdad on Friday that U.S. counterterrorism aid to Yemen would more than double in the year ahead.

Gen. David Petraeus arrived in Yemen yesterday and met with President Ali Abdullah Saleh, a Yemeni government official said.

Security officials in Yemen said yesterday the government deployed several hundred extra troops to two mountainous eastern provinces that are al-Qaida's main strongholds in the country and where Abdulmutallab may have visited.