The window for negotiations appears to have narrowed sharply after discussions between the United States and Iran ended without a breakthrough. Following the collapse of high-level talks led by US Vice-President JD Vance, President Donald Trump moved swiftly to escalate pressure on Tehran.

In posts shared on Truth Social, Trump announced that the US Navy would begin enforcing a maritime blockade targeting ships moving in and out of Iranian ports via the Strait of Hormuz. He stated that vessels found paying what he described as “illegal tolls” would not be guaranteed safe passage. The measure, he said, would take effect from 10 am Eastern Time.

US Central Command (CENTCOM) later confirmed that the restrictions would apply to all ships using Iranian coastal routes, including those along the Arabian Gulf and Gulf of Oman. Authorities warned that any vessel violating the order could face interception or seizure, regardless of nationality.

Trump also claimed that Iran’s naval strength had been severely diminished in prior operations, asserting that only smaller fast-attack crafts remained operational. He cautioned that any attempt by such vessels to approach the blockade zone would prompt immediate and forceful retaliation.

The move follows nearly 20 hours of negotiations in Islamabad that failed to resolve core disputes, particularly over Iran’s nuclear programme. While Trump suggested some progress was made on secondary matters, he maintained that Tehran refused to provide firm assurances on curbing its nuclear ambitions — an issue Washington considers non-negotiable.

Despite the setback, diplomatic channels are not entirely closed. Regional intermediaries, including Pakistan, Egypt and Turkey, are reportedly continuing efforts to revive dialogue. Sources familiar with the talks suggest bargaining is ongoing behind the scenes, though no fresh round has been announced.

Beyond the nuclear dispute, sticking points include Iran’s influence over strategic waterways, its backing of armed groups in the region, uranium enrichment limits, and the scope of sanctions relief. These layered disagreements have complicated efforts to secure a lasting accord.

The economic ripple effects were immediate. Crude oil prices climbed back above $100 per barrel as markets reacted to the heightened uncertainty around one of the world’s most vital energy corridors. Shipping traffic through the Strait of Hormuz — a key artery for global oil supply — has already been disrupted for months amid escalating tensions.

Domestically, the decision presents political challenges for Washington. Surveys indicate growing public unease over the direction of the conflict. Nonetheless, Trump projected confidence, suggesting the US economy could absorb temporary energy shocks and asserting that Iran would eventually concede to American demands.

Tehran, however, has responded defiantly. Iran’s Revolutionary Guards stated that the strait remains under their supervision and warned against any miscalculation by US forces. Officials in Tehran have also highlighted the potential consequences for American consumers, hinting that fuel prices in the United States could rise sharply if tensions intensify.

The unfolding situation leaves Washington facing a complex calculation: while the blockade increases leverage over Iran, it also risks destabilising energy markets and deepening US involvement in a volatile confrontation with no immediate resolution in sight.