The vessel, a "stateless, sanctioned dark fleet motor tanker", was apprehended in a pre-dawn operation, the military adds.
"The interdicted vessel, M/T Sophia, was operating in international waters and conducting illicit activities in the Caribbean Sea," the US military says in a statement. "The US Coast Guard is escorting M/T Sophia to the US for final disposition."
The departments of Defense and Homeland Security conducted the operation. The vessel is now being escorted to the US, according to the Southern Command.
The seizure of this vehicle comes as the US also seized a Russian-flagged oil tanker linked to Venezuela.
We can bring you some more from the US European Command now, which says the seizure of the vessel supports US President Donald Trump's "Proclamation targeting sanctioned vessels that threaten the security and stability of the Western Hemisphere".
"The operation was executed by DHS components with support from @DeptofWar, showcasing a whole-of-government approach to protect the homeland.
This latest US operation to board the Marinera follows an initial attempt to board the tanker last month in the Caribbean when it was believed to be heading towards Venezuela.
The US Coast Guard had a warrant to seize the ship, which was accused of breaking US sanctions and shipping Iranian oil. It then changed course, changed its name, and re-registered as a Russian vessel.
It had previously been falsely registered under a Guyanese flag. It has historically transported Venezuelan crude oil but is reporting to be empty at the moment.
It has since been pursued by US authorities across the North Atlantic, and Russia has reportedly deployed a submarine to help escort it across the ocean.
The latest location data from the vessel shows it made an abrupt turn to the south and slowed to eight knots starting at 11:26 GMT.
The tanker is now about 200km (124 miles) south of the Icelandic coast.
The US is carrying out an operation to seize the Venezuela-linked oil tanker Marinera, formerly known as Bella-1, a US official confirms to CBS News, the BBC's US partner.