Marco Rubio said on Wednesday at a joint briefing with Greek foreign minister Giorgos Gerapetritis in Athens that Iran will never be allowed to acquire a nuclear weapon under the Trump administration.
Rubio warned that any agreement must guarantee that Tehran cannot produce a nuclear weapon, adding that the U.S. will accept no assurances without concrete cuts to Iran's enrichment program.
Vice President J.D. Vance echoed the sentiment the day before, telling Reuters that Washington would not accept promises on the nuclear issue without a "meaningful" reduction in Iran's ability to enrich uranium to 60%.
The comments come amid a broader U.S. push to negotiate an end to the seven‑month war and reopen the Strait of Hormuz, a vital artery for global oil shipments.
Rubio also highlighted Tehran's conventional buildup, accusing it of stockpiling ballistic missiles and drones that could shield its nuclear sites from foreign strikes, and said Trump had already crippled those capabilities.
He warned the Iranian economy is collapsing under sanctions and that Tehran spends resources on regional proxies rather than domestic needs.
The next U.S.-Iran round of talks is slated for May 30 in Geneva, where negotiators will assess whether Tehran can meet the U.S. demands.