Pompeo's announcement follows a ruling by the International Court of Justice (ICJ), the United Nations' top court, on Wednesday ordering the United States to lift sanctions on humanitarian goods to Iran.
In a victory for Tehran's campaign to isolate Washington from the worldwide community, the global Court of Justice (ICJ) ordered President Trump's administration to lift sanctions on humanitarian supplies and aviation equipment entering Iran.
The sanctions may not hurt "exportation to the territory of Iran of goods required for humanitarian needs such as medicines, medical devices and foodstuffs and agricultural commodities as well as goods and services required for the safety of civil aviation", he said.
The court action brought by Iran was part of a drive on several fronts to isolate Washington, following the U.S. withdrawal from the 2015 accord which lifted sanctions in return for constraints on Iran's nuclear programme.
The court ruling was a moral victory for Tehran, even though it was hoping for a more sweeping decision on the USA withdrawal from the nuclear deal.
He then announced the US would terminate the Amity treaty which formed the basis of Iran's suit against the U.S. He also said that there are existing exemptions for humanitarians purposes in the sanctions regime. He cited a case brought to the court by the "so-called state of Palestine" challenging the move of the U.S. Embassy in Israel from Tel Aviv to Jerusalem as the main reason for withdrawing.
Despite global criticism, Washington is pushing ahead with the measures.
Iran has invoked a little known 1955 Treaty of Amity that was signed before Iran's 1979 Islamic Revolution, which caused a sharp deterioration in bilateral ties that has endured until today.
When the first round went into effect in August, President Trump said in a tweet, "These are the most biting sanctions ever imposed, and in November they ratchet up to yet another level".
He said the administration would review all accords that might subject the U.S.to prosecution by worldwide courts or panels.
Washington however forcefully told the court - which rules on disputes between United Nations member states - that it has no jurisdiction to rule on this case as it concerns a matter of national security. The court is the primary judicial arm of the United Nations. It had argued that USA sanctions, which were lifted when the agreement was implemented in 2016, violated the 1955 Treaty of Amity.
Trump last week attacked the International Criminal Court, a separate court from the International Court of Justice.
That pact saw sanctions against Tehran lifted in return for it accepting curbs on its nuclear program. Pompeo made the announcement Wednesday, saying the cancellation is "39 years overdue".
The foreign policy establishment has always been obsessed with the idea of using sanctions as a relatively low-priced, non-confrontational means of convincing rogue regimes to change their behavior, but the technique has rarely been used as seriously as the Trump administration has employed it against North Korea and Iran.