The United States and Iran have signalled cautious progress in negotiations aimed at ending their conflict, but remain sharply divided over key issues including Tehran’s enriched uranium stockpile and proposed tolls on the strategic Strait of Hormuz.
U.S. Secretary of State said Thursday that there were “good signs” of movement toward an agreement but warned that any deal would collapse if Iran pursued control measures over shipping in the vital waterway.
“No one in the world is in favor of a tolling system. It can’t happen and it would be unacceptable,” Rubio told reporters in Miami, adding that Washington would consider “other options” if diplomacy failed.
The comments come as both sides report incremental progress in talks, even as deep disagreements persist over the terms of a possible settlement to the conflict that has disrupted global energy and shipping routes.

Iran has indicated that the latest U.S. proposal has narrowed differences between the two sides, according to the semi-official Iranian Students’ News Agency (ISNA), which said Tehran is reviewing Washington’s position alongside its own earlier framework for negotiations.
However, Iranian officials have insisted that further progress will depend on what they describe as an end to “temptation for war” from the United States.
Central to the dispute is the future of Iran’s enriched uranium stockpile, which Washington wants removed from the country amid fears it could be used for weapons development.
The Iranian government maintains that its nuclear programme is entirely peaceful and has rejected demands to transfer enriched material abroad.
The issue has repeatedly stalled negotiations, with neither side willing to compromise on what it views as a core security concern.
Iran’s Supreme Leader has reportedly issued a directive opposing the transfer of near-weapons-grade uranium out of the country, according to Iranian sources cited by Reuters.
Another major sticking point is the Strait of Hormuz, a critical global energy route through which around a fifth of the world’s oil and liquefied natural gas typically passes.

The United States has rejected proposals linked to the introduction of a tolling or payment system for vessels using the waterway, arguing that it would undermine freedom of navigation.
President said the United States sought to keep the strait open and free for global shipping.
“We want it open. We want it free. We don’t want tolls. It’s international,” Trump told reporters, adding that Washington had “total control” over the waterway.
The Strait of Hormuz has become a flashpoint in the wider conflict, which escalated after strikes on Iranian targets earlier this year and has since disrupted regional maritime traffic.
Shipping through the strait has reportedly fallen sharply, with tensions deterring commercial vessels from entering the area.
Military deployments in the region remain elevated. The U.S. Central Command said on Friday that the USS Abraham Lincoln carrier strike group was maintaining “peak readiness” in the Arabian Sea as part of ongoing operations linked to enforcement of restrictions on Iranian ports.
Diplomatic efforts have also drawn in regional actors. Pakistan’s Army Chief visited Tehran on Thursday as part of mediation efforts between Washington and Tehran, according to Iranian state-linked media.
The Strait of Hormuz, located between Oman and Iran, remains one of the world’s most strategically important shipping corridors, and any prolonged disruption is expected to have significant implications for global energy markets.

Despite signs of cautious diplomatic engagement, analysts say the talks remain fragile, with both sides continuing to pursue conflicting strategic objectives.
For now, expectations of a breakthrough remain tempered by entrenched disputes over nuclear material, maritime control and regional security arrangements.