Iran Warns of Ship Seizures in Strait of Hormuz as US Prepares 'Economic D-Day' Sanctions

The standoff over the Strait of Hormuz escalated further this weekend, with Iran warning it could seize vessels violating its transit rules in the critical waterway just as U.S. Treasury Secretary Scott Bessent prepared to unveil what he has described as the most aggressive financial pressure campaign ever launched against a single country.

Bessent said the United States would unveil "the single greatest financial offensive ever" against Iran on Monday, according to CNBC, while Tehran simultaneously threatened to seize ships that violate its transit rules through the strait. Iran's self-declared Persian Gulf Strait Authority, or PGSA, warned in a series of posts on the social platform X on Sunday that vessels violating its transit rules in the Hormuz Strait could face penalties including "fines, seizure, or confiscation" during future passages. Bessent had previously written in an op-ed that an "economic D-Day is coming for Iran," warning countries that continue doing business with Tehran without providing extensive additional detail at the time.

Shipping traffic through the strait remains significantly reduced compared with pre-conflict levels, even as some vessels continue transiting the waterway. According to CNN, citing MarineTraffic data from Sunday, at least six vessels transited the Strait of Hormuz over the preceding 24-hour period, including three tankers and two cargo ships entering the Gulf of Oman, along with one tanker entering the Persian Gulf. By comparison, at least 44 vessels transited the Bab-el-Mandeb strait during the same window, including four tankers and 16 cargo ships headed to the Gulf of Aden, illustrating the extent to which shipping activity through Hormuz specifically remains suppressed relative to other regional maritime chokepoints. Iran has continued allowing some Iraqi oil tankers to pass through the strait, according to Reuters, citing Iran's state-run news agency, even as overall traffic remains low.

The economic consequences of the prolonged disruption continue to be felt domestically in the United States. According to CNN, the national average price for a gallon of gasoline stood at $4.09 on Sunday, according to AAA data, a figure roughly 37.5% higher than gas prices were before the conflict began. Despite that elevated pricing, U.S. stock futures opened flat for a second consecutive Sunday, suggesting markets have, for now, largely priced in the ongoing disruption rather than reacting with fresh volatility to each new development.

Iran's top security official, Mohsen Rezaei, has separately threatened to halt oil flow out of the Strait of Hormuz entirely should any neighboring countries choose to join the broader U.S.-led economic pressure campaign against Tehran, according to CNN's live coverage of the conflict. Iran has also formally warned that ships found violating its transit rules could face detention or confiscation, a threat that has prompted some oil companies to develop new tactics specifically aimed at helping their tankers pass through the waterway undetected.

Even as Iran maintains its hardline public posture toward the strait, signs of internal division within Tehran's leadership have continued to surface. Iranian President Masoud Pezeshkian said the country "cannot continue with war forever," according to CNN, and defended the earlier agreement Iran reached with the United States in June, even amid what CNN described as purported misgivings from Iran's supreme leader regarding that deal. That internal tension reflects the broader strain the prolonged conflict and its associated economic pressure appear to be placing on Iran's governing establishment.

Diplomatic efforts involving neighboring Oman have continued alongside the escalating rhetoric. According to CNBC, Oman's foreign minister was scheduled to visit Tehran on Tuesday to continue discussions regarding the broader arrangement and management of the Strait of Hormuz, talks that have persisted intermittently throughout the conflict even as military and economic tensions between the U.S. and Iran have continued to escalate separately.

The current standoff traces back to the earliest days of the broader Iran war, which began Feb. 28, 2026, according to Wikipedia's documented timeline of the conflict, after the United States and Israel conducted airstrikes on Iranian military targets, including the assassination of then-Supreme Leader Ali Khamenei. In direct response, Iran closed the Strait of Hormuz to all foreign shipping, with the Islamic Revolutionary Guard Corps transmitting warnings via VHF radio informing vessels that "no ship is allowed to pass the Strait of Hormuz." Iran later confirmed the closure applied specifically to what it termed "unfriendly nations," continuing to allow Iran-approved vessels, primarily petroleum shipments bound for China and India, to transit the strait, in some cases under military escort.

According to a Congressional Research Service report on the crisis, periodic Iranian attacks on shipping and retaliatory U.S. strikes against Iran severely disrupted traffic through the strait for most of the conflict's first five months. A temporary evacuation effort organized by the International Maritime Organization and Oman in late June briefly allowed stranded mariners to depart the Gulf via a southern route through Omani waters, and crossings temporarily increased following a June 17 memorandum of understanding between the U.S. and Iran, though never returning to pre-war average levels. That memorandum effectively collapsed after Iran attacked a ship in Omani waters on June 25, prompting renewed U.S. airstrikes, followed by a further round of Iranian attacks in early July that President Trump said rendered the memorandum no longer in force.

The overall human and material toll of the maritime conflict has been significant. According to Wikipedia's tracking of the crisis, the confrontation has resulted in one sunk tugboat, at least 17 damaged merchant ships, seven of which were ultimately abandoned, two merchant ships captured, 12 seafarers killed or missing, and one port worker killed with two others wounded in a separate related incident in Bahrain.

With Bessent's promised sanctions announcement expected imminently and Iran simultaneously threatening ship seizures in direct response to any broader international economic pressure campaign, the coming days are likely to prove pivotal in determining whether the fragile, reduced level of shipping traffic currently moving through the Strait of Hormuz can be sustained, or whether renewed escalation on either side further disrupts one of the world's most economically consequential maritime chokepoints, through which roughly one-fifth of global oil trade and liquefied natural gas shipments have historically passed before the conflict began.