But he said the eight unidentified nations "need a little bit more time to get to zero."
He would not rule out the Trump administration extending the waivers beyond six months Pompeo maintained that despite the waivers, "these sanctions have already had an enormous impact."
He added that Trump's policy of "maximum pressure will be fully in place as of tomorrow."
President Donald Trump removed the US from the 2015 Iran nuclear deal earlier this year, triggering the sanctions being imposed Monday.
Pompeo said they are designed to "alter the Iranian regime's behavior," especially its support of terrorist groups like Hezbollah.
Speaking to CBS' "Face the Nation" Pompeo said he was "confident" that Iran would not restart its nuclear program with the U.S. withdrawing from the deal.
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