Bombed cities support a truce (9)

I believe the answer is:

armistice

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'truce' is the definition.
(synonyms)

I don't understand the remainder of the clue.

(Other definitions for armistice that I've seen before include "Suspension of hostilities" , "harbinger of peace?" , "let-up from war" , "Fire is prevented by this" , "Cease-fire in order to conduct talks" .)

I've seen this clue in the Sydney Morning Herald.

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