WASHINGTON - US Secretary of State Antony Blinken publicly admitted Wednesday that his country's efforts spanning the last 20 years to seek regime change in Iran did not yield much success.

"I think if we look at the last 20 years, our experiments in regime change have not exactly been resounding successes," Blinken, while attending a discussion session at the Council on Foreign Relations in New York, said in remarks that saw the audience erupt in laughter.

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The secretary attributed such failure first and foremost to the nonexistence of diplomatic relations between Washington and Tehran since April 1980, when then-President Jimmy Carter severed ties with Iran following the 1979 hostage crisis at the US Embassy in Teheran.

"So from my perspective, first, the internal dynamics in Iran are complicated. And we're in many ways not necessarily the best source of a clear view on that, precisely because we, of course, don't have diplomatic relations; we've been disengaged," Blinken said.

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"I think that's hard to engineer from the outside," Blinken said. "And you inevitably end up with unintended consequences."

"I'd be very wary about trying to engineer anything from the outside," the secretary said as he wrapped up his long-winded, carefully-worded response to a question from the audience asking whether the United States should adopt a policy of regime change in Iran.