US Secretary of State Marco Rubio has firmly rejected Iran's insistence that transit fees for vessels passing through the Strait of Hormuz remain a viable option under any future administration agreement.
The clash highlights a fundamental disagreement over the legal and economic status of the chokepoint, which handles roughly a fifth of global oil consumption.
The dispute complicates ongoing efforts to finalize a framework deal aimed at ending hostilities and reopening the strategic waterway.
While Tehran argues that tolls are a legitimate revenue stream and security measure, Washington views the proposal as an unacceptable barrier to free navigation and a potential tool for coercion.
This diplomatic friction adds uncertainty to the timeline for a full resolution.
Markets remain sensitive to developments in the corridor.