By Chelsea Robin | 2026-03-13

US forces demonstrated advanced maritime capabilities, extreme endurance and global reach with last month's interdiction of three tankers carrying illicit oil from the Caribbean Sea to the Indian Ocean, officials say.

In the latest incident, US military forces seized the Bertha, a Very Large Crude Carrier subject to US sanctions for illicitly transporting Iranian and Venezuelan oil.

The seizure was the 10th tanker interdiction globally since last December and could "signal tighter scrutiny of vessels carrying crude from sanctioned countries," S&P Global reported on February 24.

Previous similar operations occurred in the Caribbean and North Atlantic, according to news reports.

Global tracking

The Bertha had departed Venezuela in early January carrying 1.9 million barrels of Merey heavy crude, according to shipping reports from Venezuelan state-owned oil and gas company PDVSA.

According to a February 24 social media post by the US Department of War, the vessel had violated Washington's Caribbean "quarantine" of sanctioned tankers. "From the Caribbean to the Indian Ocean, we tracked it and stopped it," the department added.

The Department of War said US forces conducted a "right-of-visit," maritime interdiction and boarding of the Bertha without incident in the US Indo-Pacific Command (INDOPACOM) area of responsibility after the vessel attempted to evade enforcement.

The Bertha was the third illicit oil tanker seized last month in the Indian Ocean, the Pentagon said via social media post, adding, "Three boats ran and now all three have been captured."

INDOPACOM forces interdicted the Aquila II on February 9, followed by the Veronica III on February 15. Both vessels were under sanctions imposed by the US Treasury Department.

US forces tracked the Aquila II for more than 30 days as it crossed the Caribbean Sea, the Atlantic Ocean and waters around the Cape of Good Hope before entering INDOPACOM's area of operations, according to Reuters. The Veronica III and the Bertha followed similar long-range routes after departing Venezuela in early January.

Operational reach

The operations pointed to coordination across US commands as the vessels moved from the Caribbean into INDOPACOM's area of operations.

The interdictions highlighted a capability that extends beyond traditional maritime patrols. "No other nation has the global reach, endurance or will to enforce sanctions at this distance," the Department of War posted on social media. US forces monitored multiple sanctioned vessels simultaneously for weeks as they moved illicit crude through international waters while attempting to evade detection.

Tankers involved in sanctions evasion frequently try to obscure their movements by disabling Automatic Identification System transponders, changing identities, switching registries or using ship-to-ship transfers to mask cargo origins.

To counter those tactics, US forces relied on intelligence networks, satellite monitoring and maritime patrol aircraft capable of maintaining visual and radar contact with vessels operating "dark" over long distances.

To track the vessels, US forces demonstrated multi-domain targeting and intelligence capabilities. They used the P-8A Poseidon, a long-range antisubmarine and maritime surveillance aircraft, to help maintain contact and vector in boarding teams once the ships entered the INDOPACOM area of responsibility.

Abrupt collapse of 'dark fleet' model

This shift appears to have been driven by the US government's Office of Foreign Assets Control (OFAC)'s updated Venezuela framework. After the ouster of strongman Nicolás Maduro in January, Washington eased restrictions on shipping of Venezuelan oil. The policy shift reduced incentive to use illicit tankers.

Combined with Washington's maritime enforcement campaign, the new policy has effectively neutralized the delivery phase of the illicit supply chain. While vessels such as the Bertha attempted to depart in early January, the "dark fleet" model has since "collapsed abruptly," Windward reported, noting that "not a single dark fleet tanker has successfully shipped" its cargo to a final destination since mid-December.

Artificial-intelligence (AI)-driven monitoring has supported that effort. Windward, which provides AI-powered maritime intelligence to the Department of War and other agencies, said roughly 100 tankers shipped Venezuelan crude before mid-December 2025, with about 40% under sanctions but that enforcement pressure had sharply disrupted the trade.

Partner enforcement

The US push has coincided with growing regional cooperation. Reuters reported on February 17 that India had seized three US-sanctioned tankers linked to Iran and stepped up maritime surveillance to curb illicit trade.

The Indian coast guard deployed about 55 ships and at least 10 aircraft to maintain consistent surveillance of its maritime zones and prevent Indian waters from being used for ship-to-ship transfers that disguise cargo origins, according to the report.

"International waters are not a refuge for sanctioned actors," the Pentagon said on social media. "By land, air or sea, our forces will find you and deliver justice."