Strait of Hormuz: Iran Reasserts Control After June Deal as Attacks Disrupt Global Shipping
Iran’s renewed attacks in the Strait of Hormuz after a June memorandum have sparked U.S. strikes, halted tanker traffic and sent global energy prices higher.
The Strait of Hormuz returned to the centre of a geopolitical crisis this month as Iran ramped up attacks on commercial vessels and declared control over passage following a contentious June memorandum. The agreement, hailed by U.S. leaders as a route to reopen the waterway, has been criticised for language that Tehran interprets as formal recognition of its authority over transit. In the wake of recent strikes and counterstrikes, commercial shipping has sharply diminished and the risk of wider conflict has climbed.
June memorandum and the reopening claim
The 14-point memorandum signed in mid-June was presented by U.S. officials as a pathway to restore commercial navigation through the Strait of Hormuz. It included a temporary prohibition on fees and said Iran would make “best efforts” to ensure safe passage, language that many diplomats found vague.
Critics argue the document effectively acknowledged Tehran’s role in managing transit while leaving enforcement and legal definitions unclear. That ambiguity has now become a focal point of dispute as Iranian authorities assert the right to direct shipping routes and impose conditions on passage.
U.S. naval guidance and covert escorting
In the weeks before the memorandum, U.S. naval forces quietly coordinated with commercial tankers to steer them along a southern corridor near Oman’s coast to avoid Iranian fire. The operation involved radio routing, occasional air cover and a decision by some ships to switch off automatic identification transponders to reduce detection risks.
U.S. Central Command officials say more than 800 commercial vessels used guidance along the Oman route in May and June, moving an estimated hundreds of millions of barrels of crude. Despite that assistance, commanders warned there was no absolute guarantee of protection against Iranian strikes, a vulnerability exposed when attacks resumed.
Iranian strategy and assertions of authority
Tehran has steadily built mechanisms to assert control over the strait, including the establishment of a Persian Gulf Strait Authority in May and statements that ships must obtain permission to transit. Iranian officials and analysts describe the maneuver as a restoration of sovereign rights over waters adjacent to their coastline.
Tehran has also linked security guarantees to routes near its shore, arguing that vessels choosing that corridor would be afforded protection — often for a fee during the height of the conflict. Opponents view the practice as de facto tolling that undermines longstanding international navigation norms.
Recent attacks and U.S. military response
Last week Iran struck multiple vessels transiting the southern corridor, prompting U.S. airstrikes in retaliation and a sharp escalation in military activity across the Arabian Sea. U.S. Central Command reported striking a large number of Iranian military targets as Washington sought to deter further attacks on commercial shipping.
The confrontation has included mines, missile and drone strikes that dramatically reduced the number of vessels willing to risk passage. In the days following the most recent attacks, weekly transits through the strait fell from hundreds to just a few dozen, according to maritime traffic analysts.
Economic fallout and energy market reactions
The renewed hostilities have triggered immediate reactions in global energy markets, with oil and liquefied natural gas prices rising on fears of prolonged disruption to supplies from Middle East producers. Before the conflict, roughly a fifth of the world’s oil and LNG flowed through the Strait of Hormuz, making any interruption a direct risk to international markets.
Traders and investment strategists warn that continued instability could deepen inflationary pressures already felt by many economies. The balance of economic pain — whether on Iran or on global consumers — is shaping diplomatic and military calculations in Washington and across the Gulf.
Dilemma for shipowners and regional diplomacy
Shipping companies now face a stark choice: navigate the southern route close to Oman and risk Iranian attack, or steer through the northern corridor near Iran and potentially submit to Tehran’s permissions and fees. The calculation weighs immediate physical danger against reinforcing Tehran’s control over the waterway.
Regional states and international organisations have started renewed diplomatic outreach to defuse tensions, but the June memorandum’s ambiguous wording complicates multilateral efforts. With large naval forces from multiple countries operating in the area, the potential for unintended clashes remains a central concern for diplomats.
The coming days will test whether negotiators can turn the memorandum’s temporary language into clear, enforceable guarantees that protect neutral shipping and avert a broader war.