On December 10, 2025, U.S. Coast Guard and FBI personnel boarded and seized the oil tanker MT SKIPPER in waters off the coast of Venezuela, marking one of the most significant maritime enforcement actions against “shadow fleet” vessels in recent years. The vessel was originally designated by OFAC under the name ADISA in November 2022, and is alleged to be part of an evasive oil trade that funneled revenue to the Islamic Revolutionary Guard Corps-Qods Force and Hezbollah. At the time of seizure, SKIPPER had loaded approximately 1.8 million barrels of Venezuelan heavy crude and was digitally manipulating its tracking signals to falsely indicate it was sailing off the coast of Guyana while also falsely flying the Guyana flag. The seizure raises fundamental questions about the scope of U.S. maritime authority and the legal basis for seizing vessels and cargo on the high seas.
Can the U.S. Board a Non-U.S. Vessel Outside of Its Territorial Seas?
It was legally essential that the boarding of SKIPPER was led by a U.S. Coast Guard Maritime Security Response Team (MSRT). The Coast Guard’s boarding authority statute, 14 U.S.C. § 522, is unique in U.S. law. It authorizes the Coast Guard to “make inquiries, examinations, inspections, searches, seizures, and arrests upon the high seas and waters over which the United States has jurisdiction, for the prevention, detection, and suppression of violations of laws of the United States.” As a result of the high-seas language, the authority extends well beyond the twelve-nautical-mile territorial sea, reaching into international waters.
The statute grants Coast Guard boarding officers the power to board any vessel “subject to the jurisdiction, or to the operation of any law, of the United States” and to use “all necessary force to compel compliance.” Unlike land-based law enforcement officers who generally require a warrant, Coast Guard personnel can board and inspect vessels without warrant or suspicion.
The scope of this authority is not unlimited, however. Under international law, particularly the UN Convention on the Law of the Sea (UNCLOS), vessels on the high seas are generally subject to the exclusive jurisdiction of their flag state—the country where they are registered. As a result states generally cannot unilaterally board and enforce domestic law against foreign-flagged vessel outside their own coastal waters unless UNCLOS provides an exception for doing so.
Stateless Vessels
The key to the legal framework for the SKIPPER boarding lies in the vessel’s registration status. According to maritime intelligence reports and international ship registries, the SKIPPER was falsely flying the Guyana flag and was therefore a stateless vessel. Guyana had notified the International Maritime Organization that it de-listed the ship following advocacy group listings and American sanctions. This designation as “stateless” proved crucial to the legal justification for the seizure.
Under UNCLOS and customary international law, vessels “without nationality” are treated as stateless vessels and, therefore, outside the protection of any country. When a vessel falsely claims registry under a flag it does not legitimately hold, or refuses to show any flag at all, states have the “right of visit,” allowing their officials to stop and inspect the ship on the high seas. This right of visit permits warships to verify a vessel’s nationality, and if doubts remain after checking its documents, engage in a more extensive boarding.
Multiple sources confirmed that this was the international law rationale supporting the boarding. A senior Trump administration official described it as a “judicial enforcement action on a stateless vessel.” The deliberate misrepresentation of flag state—something believed to be a common tactic among “shadow fleet” operators to evade sanctions—effectively stripped the SKIPPER of the legal protections normally afforded to vessels on the high seas.
What Authority Does the U.S. Have to Seize a Ship and Its Cargo?
While boarding authority establishes one element of lawfulness, the ability to seize a vessel and its cargo requires further authority. The seizure of SKIPPER was authorized in a warrant issued pursuant to 18 U.S.C. §§ 981, 982, 2332b(g)(5), and 2339B(a)(1), which authorize the seizure of “all assets, foreign or domestic, of any individual, entity, or organization engaged in planning or perpetrating any Federal crime of terrorism against the United States, citizens or residents of the United States, or their property.”
These statutes, found in U.S. counterterrorism laws, provide the government with powerful tools to act against terrorist financing networks. The warrant specifically cited the vessel’s identification by the Treasury Department’s Office of Foreign Assets Control as being used in an oil shipping network supporting Hizballah and the Islamic Revolutionary Guard Corps-Qods Force, both State Department-designated foreign terrorist organizations. According to the Justice Department, the IRGC uses proceeds from petroleum distribution to fund its terrorist networks.
The warrant was issued by a federal magistrate judge in the District of Columbia on November 26, 2025—more than two weeks before the actual seizure. The U.S. Attorney’s Office for the District of Columbia obtained an order unsealing the seizure warrant, and the Coast Guard executed the warrant after boarding the vessel as it traveled on the high seas after departing Venezuela.
The statutory authorities cited in the warrant represent a convergence of asset forfeiture laws and counterterrorism statutes. Section 2339B prohibits providing material support to designated foreign terrorist organizations, while sections 981 and 982 authorize civil and criminal forfeiture of property involved in illegal activities. By framing the vessel and its cargo as assets supporting terrorism, the government established a legal basis for forfeiture under federal law.
Can the U.S. Seize Any Sanctioned Vessel?
Following the SKIPPER seizure maritime operators are prone to ask, does every vessel on OFAC’s sanctions list face potential boarding and confiscation? The answer comes from the underlying legal authority for nearly all sanctions enforcement, particularly the International Emergency Economic Powers Act (IEEPA). While IEEPA does authorize blocking transactions, freezing bank accounts, and prohibiting U.S. persons from dealing with sanctioned entities, it does not contain a generally applicable seizure and forfeiture provision like those under which the SKIPPER warrant was issued. While these are impactful measures, they do not transfer title in property.
The absence of a seizure and forfeiture provision actually distinguishes IEEPA from its predecessor, the Trading with the Enemy Act (TWEA), which did include “vesting” authority for permanent seizure during wartime. Congress deliberately omitted these powers from IEEPA when enacting it in 1977 because IEEPA was designed for peacetime emergencies. With no seizure or “vesting” authority, sanctioned vessels are not subject to the type of seizure carried out on SKIPPER.
However, IEEPA operates through blocking and freezing mechanisms, not seizure authority. The statute does not contain a provision authorizing the government to physically seize and confiscate property. Blocking freezes property in place and prohibits transactions, while seizure involves taking physical custody and control. This distinction is crucial: violations of IEEPA sanctions programs alone cannot give rise to seizure like that of the SKIPPER. A vessel that violates sanctions by carrying prohibited cargo or conducting transactions with sanctioned entities may be subject to penalties, fines, and blocking designations, but IEEPA itself provides no mechanism for the government to board and seize the vessel on the high seas.
The seizure of MT SKIPPER underscores how our understanding of what the law allows can be shaped by ordinary practice rather than the law itself. It is a compelling reminder that legal authorities exercised day in and day out by maritime states can be applied more creatively to accomplish what at first blush appears to be outside law’s reach. The U.S. leveraged three key legal elements: the Coast Guard’s broad boarding authority under 14 U.S.C. § 522, the vessel’s stateless status under international maritime law, and terrorism-related asset forfeiture statutes that reach beyond typical IEEPA sanctions enforcement and act against the threat perceived in the “shadow fleet.”
While the operation demonstrates sophisticated use of existing legal authorities, it also highlights unresolved tensions in international maritime law. The step from establishing statelessness and boarding rights to full seizure and confiscation occurs in what scholars describe as a “jurisdictional grey zone”—an area where domestic law claims authority but international law principles remain unsettled. The precedent set by the SKIPPER seizure suggests that shadow fleet vessels operating with falsified registrations face not merely financial penalties but physical interdiction and asset forfeiture, fundamentally altering the risk calculus for sanctions evasion. Yet this enforcement model depends critically on the combination of statelessness, terrorism connections, and domestic judicial process—a formula that may not apply uniformly to all sanctioned vessels.
For more information concerning the U.S. authority to board and/or seize vessels, please contact us at: info@chaloslaw.com