Iran accused the US of "contradictory behavior and provocative statements" after the US warned Iran of consequences for backing the Houthis and imposed new sanctions.
In January, 70% of those who supported Trump said they had high confidence in his handling of Iran.
While hopes were high at the first and second meetings, some of those hopes appeared to fade in the last week.
The US and Iran prepare to hold a third round of talks this weekend on a possible deal to reimpose restraints on Tehran's nuclear program.
These statements were supposed to be delivered by the Iranian foreign minister as part of the Carnegie Endowment for International Peace think tank’s conference.
Trump’s strategy toward Iran rests on three key pillars: withdrawing from the nuclear deal and reimposing crippling economic sanctions, applying military pressure with explicit threats of force.
Iran and the US held a second round of talks in Rome, with plans to continue next week, as Tehran seeks a 'comprehensive' deal and maintains strong ties with Russia.
Washington wants Iran to halt production of highly enriched uranium, which it believes is aimed at building an atomic bomb.
Tehran has approached the talks warily, doubting the likelihood of an agreement and suspicious of Trump, who has threatened to bomb Iran if there is no deal.
Trump warned Iran to abandon its nuclear program or face harsh consequences.