"Al Qaeda in the Arabian Peninsula is an extension of Al Qaeda core coming out of Pakistan. And, in my view, it is one of the most lethal and one of the most concerning of it," John Brennan, assistant to the US President for Counterterrorism and Homeland Security, told media persons at a White House briefing.
He said that they have moved forward to try to execute this attack against the homeland.
"I think (they) demonstrated to us that we had a strategic sense of sort of where they were going, but we did not know they had progressed to the point of actually launching individuals here. We have taken that lesson, and so now we are full on top of it," Brennan said.
The US official termed the Nigerian terror suspect Umar Farouk Abdulmutallab as a terrorist, who unsuccessfully tried to blow up a NorthWest Airlines plane on December 25 over Detroit with some 300 people on board.
"He is a terrorist now," said Brennan.
Abdulmutallab has been charged with blowing up a US plane on December 25. He has told FBI officials that he was trained by Al Qaeda operatives in Yemen where he received the explosives to blow up the plane mid-air.
"As far as being a known terrorist, we knew that Abdulmutallab had departed from Nigeria and was in Yemen associating with extremists. This came directly from his father. We knew from that stream of information that he was extremist and had those radical tendencies," Brennan said in response to a question.
Brennan said Al Qaeda is an organisation that was dedicated to murder and wanton slaughter of innocents.
"What they have done over the past decade and a half, two decades, is to attract individuals like Abdulmutallab and use them for these types of attacks," he said, adding that he was motivated by a sense of religious sort of drive.
Unfortunately, Al Qaeda has perverted Islam and has corrupted the concept of Islam, so that he is able to attract these individuals. But Al Qaeda has the agenda of destruction and death," the top counterterrorism official said, adding that Al Qaeda was just determined to carry out attacks on the US.