The U.S. military is preparing to board and potentially seize Iran-linked ships in the coming days, according to U.S. officials. That intention marks a shift from enforcing a local blockade in the Persian Gulf to a broader campaign that could reach vessels in international waters. The move is meant to choke off revenue streams for Tehran by targeting oil shipments and other cargoes linked to the Iranian regime, including the so-called dark fleet and vessels holding floating storage of crude.
The expansion comes as the Strait of Hormuz has become more contested, with Iran’s Revolutionary Guard tightening control and warning that ships attempting to cross could be attacked. Several commercial vessels have reported coming under fire from projectiles and fast boats, forcing some to turn back. The U.S. response—sustaining a maritime blockade until a negotiated arrangement is reached—has been accompanied by plans to exercise authority well beyond immediate regional waters in order to deny Iran the ability to monetize its petroleum assets.
How boarding and seizures would be executed
There are multiple boarding methods the U.S. can employ depending on threat level. Routine inspections are typically handled by visit, board, search, and seizure (VBSS) teams, while high-risk operations can involve SEAL teams or maritime raid forces from the Marine Corps. The VBSS doctrine focuses on rapid control and search of a vessel, while maritime raids emphasize speed and force to seize hostile or noncompliant ships. The Coast Guard also plays a role in interdictions, having been central in previous operations against sanction-evasion networks.
Tools, units and recent training
Marine Expeditionary Units (MEUs) deploy with amphibious assault ships and specialized boarding detachments: a standard MEU brings three large ships and roughly 2,200–2,500 Marines. In recent weeks units have conducted training consistent with interdiction missions, including night boardings and close-quarters work aboard amphibious platforms. Public Defense Department imagery and posts have shown Marines drilling on ships such as USS Tripoli and USS Portland, underscoring that the Marines and naval forces are preparing to undertake maritime interception operations at short notice.
Strategic objectives and the intended pressure on Tehran
The principal aim of the expanded campaign is economic pressure: by interdicting oil shipments and denying access to floating stocks, Washington seeks to erode revenue streams that fund Iran’s military and proxy activities. Targeting the shadow fleet—tankers that obscure ownership or route oil through complex transfers—is central to this approach. U.S. leaders have signaled that the effort is intended not only to reduce immediate income but also to influence buyers and intermediaries, including nations that receive a majority of Iranian crude.
Why the reach matters
Extending operations beyond the Persian Gulf could catch shipments that were already at sea when the blockade was imposed, preventing Tehran from escaping the economic squeeze. Yet this breadth also raises diplomatic and legal complexities: seizing vessels on the high seas involves close coordination among service branches and careful legal justification for boarding foreign-flagged ships, particularly when those vessels are en route to third countries.
Risks, maritime disruption and international reaction
The operation carries significant hazards. Military planners warn that any broader kinetic moves—such as seizing islands to force open waterways—would leave forces exposed to Iranian ballistic missiles, drones, mines and swarming fast boats. Analysts describe the Strait as a potential kill box where anti-ship threats concentrate. Meanwhile commercial shipping is already responding: some tankers have diverted to avoid interdiction, and maritime authorities report vessels turning back after reported attacks. Governments whose-flagged ships were affected have registered diplomatic protests, illustrating the wider geopolitical fallout of intensified naval actions.
As U.S. forces prepare to implement a wider interdiction campaign, the outcome will hinge on operational discipline, legal framing and international support. The planned boardings aim to tighten an economic vise on Tehran, but they also increase the stakes in a maritime standoff that could reshape shipping patterns and regional security in the coming days.
