"Pursuit of Terrorists Is Irreversible," Yemen's President Says President Obama's counterterrorism adviser, John O. Brennan, met with Yemen's president, Abdu Rabbu Mansour Hadi, on Sunday, a day after a stepped-up campaign of American airstrikes reportedly killed 11 militants allied with Al Qaeda's Yemeni affiliate. The meeting in Sana, the Yemeni capital, reflected the close cooperation of the two countries in attacking the affiliate, Al Qaeda in the Arabian Peninsula, whose latest plot to bomb a United States-bound airliner was foiled last month when the would-be suicide bomber turned out to be an agent working with Saudi and Western intelligence services. Mr. Hadi has supported the campaign against the terrorist group even more strongly than his predecessor, Ali Abdullah Saleh, American officials say. "The move toward the pursuit of terrorists is irreversible," Mr. Hadi said on Sunday, praising the cooperation between Yemen's military and its tribes, according to a statement from the Yemeni Embassy in Washington. Mr. Brennan "reiterated President Obama's strong commitment to the steps taken by President Hadi to stabilize Yemen," the statement said. The thwarted plot, whose leak was the subject of a political flap on Sunday, has intensified the hunt for a Qaeda bomb maker, Ibrahim Hassan al-Asiri, who is believed to have designed a new nonmetallic bomb as well as the explosives used in previous plots against aircraft in 2009 and 2010. Senator Dianne Feinstein, Democrat of California and chairwoman of the Senate Intelligence Committee, said on "Fox News Sunday" that the infiltration of Al Qaeda and disruption of the plot was "an impressive win for the C.I.A." But she said there were now "prodigious efforts" to find Mr. Asiri. "I am hopeful that we will be able to, candidly, kill this bomb maker and kill some of his other associates because there is a dangerous process in play at the present time," Ms. Feinstein said. The Central Intelligence Agency and the Defense Department have worked closely on airstrikes against the Qaeda affiliate, mostly using drones. Officials on Sunday declined to say which agency was behind the two strikes on Saturday, which made four strikes in a week. On the CBS News program "Face the Nation," the Republican chairman of the House Intelligence Committee, Representative Mike Rogers of Michigan, accused the White House of engaging in "premature chest-thumping" about the foiled plot in the face of C.I.A. efforts to keep it secret. He also said the administration had failed to brief the Congressional intelligence committees on the unfolding plot, as required by law. But a spokesman for the National Security Council, Tommy Vietor, said Mr. Rogers's assertion was "absolutely false." "The White House and C.I.A. worked together to try and prevent publication of this damaging leak," Mr. Vietor said of the initial report on the plot by The Associated Press. We then worked together to delay the story so that we could triage and protect operational equities.