A U.S. official, privy to a recent operation, confirmed the pursuit of a tanker as part of a broader crackdown on illegal activities. This follows the U.S. administration’s announcement on Saturday of its second tanker seizure in less than two weeks.

Speaking anonymously due to the ongoing nature of the operation, the official revealed that Sunday’s pursuit targeted a “sanctioned dark fleet vessel involved in Venezuela’s illegal sanctions evasion.” The vessel was reportedly flying a false flag and was subject to a judicial seizure order.

Reuters was the first to report on the Coast Guard’s chase of the tanker.

The seizure on Saturday occurred before dawn and involved a Panama-flagged vessel named Centuries. The White House described this vessel as part of a “shadow fleet,” allegedly used to traffic stolen oil from Venezuela under a false flag.

Saturday’s predawn seizure of a Panama-flagged vessel called Centuries targeted what the White House described as a “falsely flagged vessel operating as part of the Venezuelan shadow fleet to traffic stolen oil.”

The Coast Guard, with assistance from the Navy, seized a sanctioned tanker called Skipper on December 10, another part of the shadow fleet of tankers that the US says operates on the fringes of the law to move sanctioned cargo. It was not even flying a nation’s flag when it was seized by the Coast Guard.

President Donald Trump, after that first seizure, said that the US would carry out a “blockade” of Venezuela. It all comes as Trump has ratcheted up his rhetoric toward Venezuelan President Nicolás Maduro.

This past week Trump demanded that Venezuela return assets that it seized from US oil companies years ago, justifying anew his announcement of a “blockade” against oil tankers traveling to or from the South American country that face American sanctions.

Trump cited the lost US investments in Venezuela when asked about his newest tactic in a pressure campaign against Maduro, suggesting the Republican administration’s moves are at least somewhat motivated by disputes over oil investments, along with accusations of drug trafficking. Some sanctioned tankers already are diverting away from Venezuela.

US oil companies dominated Venezuela’s petroleum industry until the country’s leaders moved to nationalize the sector, first in the 1970s and again in the 21st century under Maduro and his predecessor, Hugo Chávez. Compensation offered by Venezuela was deemed insufficient, and in 2014, an international arbitration panel ordered the country’s socialist government to pay US$1.6 billion ($2.42 billion) to ExxonMobil.

Maduro said in a message Sunday on Telegram that Venezuela has spent months “denouncing, challenging and defeating a campaign of aggression that goes from psychological terrorism to corsairs attacking oil tankers”.

He added: “We are ready to accelerate the pace of our deep revolution!”

The targeting of tankers comes as Trump has ordered the Defence Department to carry out a series of attacks on vessels in the Caribbean and eastern Pacific Ocean that his administration alleges are smuggling fentanyl and other illegal drugs into the United States and beyond.

At least 104 people have been killed in 28 known strikes since early September. The strikes have faced scrutiny from US lawmakers and human rights activists, who say the administration has offered scant evidence that its targets are indeed drug smugglers and that the fatal strikes amount to extrajudicial killings.

Trump has repeatedly said Maduro’s days in power are numbered. White House chief of staff Susie Wiles said in an interview with Vanity Fair published last week that Trump “wants to keep on blowing boats up until Maduro cries uncle.”

Democrat Senatro Tim Kaine told NBC’s Meet the Press on Sunday that Trump’s use of military to mount pressure on Maduro runs contrary to Trump’s pledge to keep the US out of unnecessary wars.

Democrats have been pressing Trump to seek congressional authorisation for the military action in the Caribbean.

“We should be using sanctions and other tools at our disposal to punish this dictator who is violating the human rights of his civilians and has run the Venezuelan economy into the ground,” Kaine said.

“But I’ll tell you, we should not be waging war against Venezuela. We definitely should not be waging war without a vote of Congress.”