US Vice President JD Vance said Washington would judge Tehran by its actions rather than its rhetoric, saying the purpose of the negotiations was to determine whether Iran was willing to make meaningful concessions.
"Part of what we're trying to do in this negotiation is to see how serious they actually are," Vance told Fox News. "And to be serious, they've got to not just say the right things. They've got to make real concessions."
"We care a lot less about what the Iranians say. We care a lot more about what they do," he said. "The thing I've learned from the president of the United States is whether friend or foe, you shouldn't trust anybody, you should trust people's actions."
"If they act in the right way, if they behave in the right way, they get a lot of benefits."
Vance said the administration was seeing both positive and negative signals from Iran and would continue following President Donald Trump's direction in the negotiations.
He added that even if diplomacy failed, Washington believed it had already achieved its principal objective.
"If... the Iranians don't behave, if they don't make the concessions in the negotiations that we need to see, their nuclear program is still destroyed, their conventional military is still destroyed, and the United States is still in a much stronger position relative to the Iranians," he said.
"We have all the cards in the negotiation. We obviously want it to be successful, but even if it's not successful, we've accomplished the core mission, which is to ensure that the Iranians never have a nuclear weapon."
