President Donald Trump said Monday that the U.S. is still actively pursuing a sanctioned oil tanker linked to Venezuela, but that he's confident the vessel will be seized.

Oil exports, the country’s financial lifeblood, have plummeted after the United States took action against three ships that have been used to carry its crude.

Trump – who last week ordered a “complete” blockade of sanctioned tankers going in and out of Venezuela – noted the US will keep oil seized during the interdiction of oil tankers in the Caribbean, lea...