WASHINGTON — The FBI is analyzing a sophisticated explosive device, similar to the underwear bomb used in an attempt to blow up a passenger jet over Detroit in 2009, that U.S. officials believe was built by Al Qaeda's affiliate in Yemen in an effort to target Western aircraft.

U.S. officials said Monday that no one was captured by U.S. agencies as part of the operation. The officials emphasized that they found no sign of an active plot to use the new bomb design against U.S. aviation or U.S.-bound jetliners.

The device was given to the CIA by a government outside Yemen, officials said. The White House said President Obama was informed of the discovery in April by John Brennan, his top counter-terrorism advisor, and was assured it "did not pose a threat to the public."

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