US President Donald Trump has ordered a total and complete blockade of all sanctioned oil tankers entering and leaving Venezuela - a move denounced by Caracas as warmongering threats.

Trump wrote that Venezuelan President Nicolás Maduro's government had been designated a foreign terrorist organisation (FTO), which had also engaged in Drug Smuggling, and Human Trafficking.

His remarks come after the US seized an oil tanker off the coast of Venezuela last week, a significant action in light of the South American nation's reliance on oil.

The US has also recently conducted deadly strikes on alleged Venezuelan drug-smuggling boats and has significantly built up its naval presence nearby.

Trump's post did not provide further detail on the enforcement of the extensive blockade on sanctioned oil tankers.

As of last week, more than 30 of the 80 ships in Venezuelan waters or approaching the country were under US sanctions, according to data compiled by TankerTrackers.com.

Multiple new US sanctions on ships said to be carrying Venezuelan oil were issued after the tanker was seized, along with sanctions on some of President Maduro's relatives.

In his Truth Social post on Tuesday, Trump asserted that Venezuela was completely surrounded by the largest Armada ever assembled in the History of South America. He indicated that this presence would only get bigger.

Yet Trump's blockade not only raises alarms about military intervention but also highlights the ongoing strife over oil resources, with Maduro's government alleging that the US seeks to seize it.

With the situation intensifying, the international community watches closely as both nations navigate these tumultuous waters.