The plane used by the U.S. military to strike a boat accused of smuggling drugs off the coast of Venezuela last fall was painted to look like a civilian aircraft, a move that appears to be at odds with the Pentagon’s manual on the laws of war.

The plane, part of a secret U.S. fleet used in surveillance operations, also was carrying munitions in the fuselage, rather than beneath the aircraft, raising questions about the extent to which the operation was disguised in ways that run contrary to military protocol.

Details of the plane’s appearance, first reported Monday by The New York Times, were confirmed by two people familiar with the situation who spoke on condition of anonymity to discuss the sensitive matter.

Pentagon press secretary Kingsley Wilson said in a statement that “the U.S. military utilizes a wide array of standard and nonstandard aircraft depending on mission requirements.”