A U.S. official tells ABC News that the U.S. Coast Guard is “in active pursuit of a sanctioned dark fleet vessel that is part of Venezuela’s illegal sanctions evasion.”

“It is flying a false flag and under a judicial seizure order,” the official added.  

The action comes after the U.S. Coast Guard seized an oil tanker off the coast of Venezuela on Saturday, just ten days after the seizure of a sanctioned oil tanker.

Unlike that first vessel seized, the tanker seized Saturday is not on any sanctions list maintained by the U.S., EU, U.K. or U.N., according to Kpler, a data firm that tracks transportation and logistics networks.

Homeland Security Secretary Kristi Noem confirmed Saturday’s operation in a post on social media, saying that the Coast Guard “apprehended” the tanker with support from the Department of Defense in a pre-dawn action. She said the tanker had last made port in Venezuela.

“The United States will continue to pursue the illicit movement of sanctioned oil that is used to fund narco terrorism in the region,” Noem said in the post. “We will find you, and we will stop you.” 

Last week, President Trump threatened to impose what he called “a total and complete blockade of all sanctioned oil tankers” traveling to and from Venezuela – a move that could devastate the Venezuelan economy, since oil exports are the lifeblood of President Nicholas Maduro’s regime.

In response to Trump’s announcement, Maduro said Venezuela would continue to trade oil and that Trump’s “intention” is regime change.

“This will just not happen, never, never, never – Venezuela will never be a colony of anything or anyone, never,” Maduro said.

 The U.S. has amassed the largest military presence in the Caribbean in decades, including the world’s largest aircraft carrier.

The Pentagon also has so far struck 28 alleged drug boats in the Caribbean and Eastern Pacific, killing at least 100 people, without providing any public evidence that the boats were carrying illegal drugs or identifying those killed.