CIA Director David H. Petraeus, right, testifies before Congress with Director of National Intelligence James Clapper. (Mark Wilson — Getty Images)

Al-Qaeda has been decimated by a barrage of U.S. operations in recent months but remains determined to attack American targets, U.S. officials said Tuesday during a rare joint hearing of the House and Senate intelligence committees.

Testifying publicly for the first time as CIA director, retired Gen. David H. Petraeus said the killing of Osama bin Laden and subsequent blows have created “an important window of vulnerability for the core al-Qaeda organization.”

Sen. Dianne Feinstein (D-Calif.), the chairwoman of the Senate Intelligence Committee, said the pace of American against al-Qaeda has meant “more killed in rapid succession than at any time since Sept. 11.”

Nevertheless, officials warned that al-Qaeda remains a significant threat to the United States because of a new willingness to embrace smaller-scale attacks, as well as the emergence of lethal affiliates including al-Qaeda’s franchise in Yemen.

Petraeus described al-Qaeda in the Arabian Peninsula as “the most dangerous regional node in the global jihad,” and said that the CIA has seen new signs of “al-Qaeda’s efforts to carry out relatively small attacks that would … generate fear and create the need for costly security improvements.”

Petraeus’s remarks came during a hearing meant to serve as a status report on the evolution of al-Qaeda, and the performance of U.S. intelligence agencies, following the 10-year anniversary of the Sept. 11 attacks.

The hearing marked the first time that the House and Senate intelligence committees had met together in a public session since 2002, when the panels collaborated on the first major investigation of the intelligence failures related to Sept. 11.

Petraeus testified alongside Director of National Intelligence James Clapper, the latest occupant of a position that was created as part of the sweeping reforms adopted after the Sept. 11 attacks.

Clapper said the intelligence community has reason “to take pride, but it would be an error to conclude that we have reason to gloat, reason to soften our focus, or reason to reduce our concerns.”

Clapper said that U.S. spy agencies have made dramatic improvements in their ability to share information and coordinate operations against terrorist groups. But he stressed the need for further changes, and officials pointed to the insurgent attack on the U.S. Embassy in Kabul as an indication of the resilience of extremist groups.

Indeed, Petraeus said that pressure on al-Qaeda and Taliban elements in Pakistan – driven mainly by the CIA drone campaign – may lead some mid-level al-Qaeda members to “seek safehaven across the border in Afghanistan or decide to leave South Asia.”

In effect, he was warning of the possibility of a return to the country that al-Qaeda fled nearly a decade ago.