New York (CNN Business) Oil prices fell swiftly on Tuesday after President Donald Trump fired Iran hawk John Bolton as national security adviser.

The surprise exit of Bolton prompted speculation that the tensions between the United States and Iran could ease, or at least that the chance of a military conflict had decreased.

Bolton was a strong proponent of the Trump administration's "maximum pressure" campaign against Iran. That campaign was built on tough sanctions that caused Iran's oil exports to plunge.

US oil tumbled as much as 2.2% to $57.30 a barrel immediately after Trump tweeted out the firing of Bolton. Crude bounced off those lows and was recently trading around $57.75 a barrel.

"This is a knee-jerk reaction given that Bolton has been so adversarial with Iran," said Matt Smith, director of commodity strategy at ClipperData. "With his removal, there is an expectation there won't be as much vehemence in the tit-for-tat with Iran."

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