Iran has announced plans to fully block the Strait of Hormuz, a move that would severely disrupt global energy supplies, following the suspension of communication with the United States through intermediaries.
The decision, reported by state media, marks a sharp escalation in ongoing tensions and alleged ceasefire violations in the region.
The threat to close the chokepoint, through which roughly a fifth of the world's oil passes, introduces significant uncertainty for maritime trade.
Markets are likely to price in heightened route exposure and potential freight disruptions as the risk of a physical blockade materializes.
Shipping insurers and tanker operators are expected to reassess risk premiums for vessels transiting the narrow waterway.
This development contrasts with earlier reports suggesting a potential easing of tensions.