Cairo. The United States is preparing to enforce a sweeping naval blockade on Iran’s ports, escalating tensions in the Middle East as Tehran warns it could target ports across the region in response.

The move, announced by US Central Command, is aimed at pressuring Iran to reopen the Strait of Hormuz and accept terms in ongoing negotiations to end a conflict that erupted in late February following US and Israeli strikes on Iranian targets.

Iran has effectively restricted access to the strait, through which about 20% of global oil trade passes in normal times, allowing limited transit while imposing high fees on some vessels. The disruption has driven up global energy prices and raised concerns about broader economic fallout.

It remained unclear whether the US blockade had fully taken effect at the scheduled time on Monday. A maritime advisory issued by the United Kingdom Maritime Trade Operations said the restrictions covered “the entirety of the Iranian coastline,” including ports and energy infrastructure, though transit through the strait to non-Iranian destinations was not officially blocked.

Still, the notice warned of increased military presence and heightened risks for commercial shipping.

The standoff has sharply reduced maritime traffic. According to shipping data, vessel movements through the strait have dropped significantly since the outbreak of hostilities, with only a fraction of the usual daily crossings recorded in recent days.

Iran responded with sweeping threats. State media warned that if its access to maritime routes is curtailed, “no port” in the Persian Gulf or Gulf of Oman would be safe, raising fears of a wider regional escalation involving US-allied states.

The confrontation comes after ceasefire talks between Washington and Tehran, held over the weekend in Pakistan, ended without agreement. Key sticking points included Iran’s nuclear program, sanctions relief, and regional security commitments.

US Vice President JD Vance said negotiations stalled after Iran refused to meet Washington’s conditions, including halting uranium enrichment and dismantling key nuclear facilities. Iran maintains its nuclear program is for peaceful purposes.

President Donald Trump, in a social media post, warned that any Iranian vessels approaching the blockade would be “immediately eliminated,” while claiming significant damage had already been inflicted on Iran’s naval capabilities.

Iranian officials struck a defiant tone. Parliamentary figures dismissed the blockade threat as exaggerated but warned of retaliation if military pressure intensifies. “If you fight, we will fight,” said parliament speaker Mohammad Bagher Qalibaf.

Analysts say the unfolding crisis presents a high-stakes test of endurance. A blockade could deepen Iran’s economic strain, but it also risks pushing global oil prices higher, potentially creating political pressure in the United States and beyond.

Brent crude prices rose about 7% to around $102 per barrel, up from roughly $70 before the conflict began, amplifying concerns about inflation and supply disruptions worldwide.

European leaders are seeking to contain the crisis. British Prime Minister Keir Starmer said he would coordinate with French President Emmanuel Macron to push for renewed diplomatic efforts and the reopening of the strait without conditions.

The current ceasefire is set to expire on April 22, with no clear path forward. The conflict has already caused widespread casualties and infrastructure damage across multiple countries in the region.

Diplomatic efforts are expected to continue, with Pakistan and Türkiye offering to facilitate further talks. But with both sides hardening their positions, the risk of renewed conflict and broader economic disruption remains high.