There has been a build up of pressure on the Venezuelan government since Trump began his second term in office last January.

First, the Trump administration doubled the reward it offered for information leading to the capture of Maduro.

In September, US forces began targeting vessels it accused of carrying drugs from South America to the US.

There have been more than 30 strikes on such vessels in the Caribbean and the Pacific since then, killing more than 110 people.

The Trump administration blames Maduro for hundreds of thousands of Venezuelan migrants entering the US. 

Without providing evidence, Trump accused Maduro of "emptying his prisons and insane asylums" and "forcing" its inmates to migrate to the US. 

The US president also claims the Venezuelan government is allowing oil money to fund drug-related crime, alleging that Maduro himself is a cartel leader.

Maduro vehemently denies this and accuses the US of using its "war on drugs" as an excuse to try and overthrow him and access Venezuela's vast oil reserves.