If a law enforcement officer who has detained a person under Rule 3.1 reasonably suspects that the person is armed and presently dangerous to the officer or others, the officer or someone designated by him may search the outer clothing of such person and the immediate surroundings for, and seize, any weapon or other dangerous thing which may be used against the officer or others. In no event shall this search be more extensive than is reasonably necessary to ensure the safety of the officer or others.