The fleet of ghost ships Venezuela uses to smuggle part of its oil to black markets, which President Donald Trump vowed this week to stop with a military blockade, is made up of dozens of old tankers and operates following the example of other nations under sanctions such as Russia and Iran,

The move is an escalation of military operations and a pressure campaign against Nicolás Maduro, Venezuela’s leader. But its scope and economic impact are not clear.

President Donald Trump ramped up pressure on Venezuela on Tuesday by announcing that he is ordering a blockade of all “sanctioned oil tankers ” entering and leaving the South American country.

Trump orders total blockade of Venezuelan oil tankers as the South American nation controls world's largest oil reserves with over 300 billion barrels.