There was apparently an attempt to blow up a passenger jet today, but the bomb failed to detonate. Details are still sketchy.

WASHINGTON — A Northwest Airlines passenger landing in Detroit on Friday tried to blow up the flight but the explosive device failed, two U.S. national security officials said.

The passenger, who was traveling on Northwest Airlines Flight 253 from Amsterdam, was not identified. He was being questioned Friday evening, according to one of the officials, both of whom spoke on condition of anonymity because the investigation was continuing.

The motive of the Christmas Day attack was not immediately clear.

“He appears to have had some kind of incendiary device he tried to ignite,” said one of the U.S. officials.