The US president shared an image of himself looking off-camera while striding forward on top of a moody grey background.
The words: "Sanctions are coming. November 5" run across this chest.
The font is the same as that used in hit TV show Game of Thrones and the wording is a riff on one of the famous lines from the series "Winter is Coming".
The post appears to allude to Mr Trump reinstating sanctions against Iran that had been removed under the 2015 nuclear deal.
At the time of the announcement, The White House said it was "the toughest sanctions regime ever imposed on Iran" and targeted Iran's energy, shipping and banking sectors.
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"Winter is Coming" is the motto of one of the main families in the show, the Starks. It is a reference to being vigilant and in a state of preparedness for any danger or hardship.
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It comes as the US says global oil supplies will exceed demand next year, making it easier for countries to cut Iranian oil imports to zero.
Brian Hook, the US special representative for Iran, told reporters that Saudi Arabia had been "very helpful" in
bolstering oil supplies while the US moved to reimpose sanctions against Tehran.