WASHINGTON, Dec 24 (Reuters) - The White House has ordered U.S. military forces to focus almost exclusively on enforcing a "quarantine" of Venezuelan oil for at least the next two months, a U.S. official told Reuters, indicating Washington is currently more interested in using economic rather than military means to pressure Caracas.

The U.S. is 'in active pursuit' of an oil tanker after President Donald Trump announced a total blockade of Venezuela's oil exports.

Venezuela has accused the United States of the "greatest extortion" at an emergency session of the UN Security Council in New York. Washington's seizure of two Venezuelan oil tankers was "worse than piracy," the Venezuelan ambassador to the UN said.

A sanctioned oil tanker pursued by US forces turned away from Venezuela and retreated out into the Atlantic Ocean, according to people familiar with the matter, as the Trump administration continues a blockade piling pressure on Caracas.

Under international law, Venezuela has control over its own oil — but its efforts to nationalize its oil industry in 2007 did result in arbitration.

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

The pursuit of the tanker, off the coast of Venezuela, is the second such operation this weekend and the third in less than a week.

The U.S. is gathering more manpower and weaponry to seize the sanctioned Bella 1 as it flees in the Atlantic.

The U.S. Coast Guard is pursuing an oil tanker in international waters near Venezuela, officials told Reuters, in what would be the third such operation in less than two weeks if successful.

A Venezuela-bound vessel fled after rebuffing an attempt by the Coast Guard to seize it, the latest twist in the escalating U.S. pressure campaign against the Maduro government.

Crude futures picked up from early losses and added to yesterday’s gains as the U.S. stepped up actions in the Caribbean to cut off Venezuela’s oil trade and increased pressure on the country’s strongman Nicolás Maduro.

The president has previously argued that the U.S. should have taken Iraq's oil after the 2003 invasion, telling ABC News in 2015, "You win the war and you take it"