The Nigerian man accused of trying to use a bomb hidden in his underwear to bring down a Detroit-bound airliner on Christmas Day has been cooperating with investigators since last week and provided fresh intelligence in multiple terrorism investigations, officials said Tuesday.

Umar Farouk Abdulmutallab's cooperation could prove to be a national security victory and a political vindication for President Barack Obama, who has been under fire from lawmakers who contend the administration botched the case by giving Abdulmutallab the right to remain silent, rather than interrogating him as a military prisoner.

In the days following the failed bombing, a pair of FBI agents flew to Nigeria and persuaded Abdulmutallab's family to help them. When the agents returned to the U.S., Abdulmutallab's family came, too, according to a senior administration official briefed on the case who spoke on condition of anonymity because of the sensitivity of the case.

FBI officials continue to question Abdulmutallab, working in collaboration with CIA and other intelligence authorities, the official said.

Authorities had hoped to keep Abdulmutallab's cooperation secret while they continued to investigate his leads, but details began to trickle out during testimony Tuesday on Capitol Hill.

In a terse exchange, FBI Director Robert Mueller appeared to confirm that Abdulmutallab is now talking with investigators.

Senate Intelligence Committee Chairman Dianne Feinstein, D-Calif., asked Mueller: "It is also my understanding that Mr. Abdulmutallab has provided valuable information. Is that correct?

"Yes," Mueller replied.

"Thank you," Feinstein said, "and that the interrogation continues despite the fact that he has been Mirandized?"

"Yes," Mueller said. He explained that Abdulmutallab did talk to FBI agents after he was arrested on Christmas Day, speaking freely until he went into surgery for burns on his legs.

Director of National Intelligence Dennis Blair also confirmed that authorities continued to get intelligence in Abdulmutallab's case.

In Detroit, U.S. Attorney Barbara McQuade declined to comment. A message seeking comment was left with Abdulmutallab's lawyer, Miriam Siefer.