The Trump administration has decreed sanctions against Venezuelan Vice-President Tareck El Aissami, the US Treasury Department says, accusing him of playing a major role in international drug trafficking.

Key points: Accusations against Mr El Aissami include international drug trafficking and aiding Hezbollah

Accusations against Mr El Aissami include international drug trafficking and aiding Hezbollah Mr El Aissami will be barred from entering the US and 13 companies owned by a businessman believed to be his frontman will be blocked

Mr El Aissami will be barred from entering the US and 13 companies owned by a businessman believed to be his frontman will be blocked Venezuela's Government is deeply unpopular and has faced mass demonstrations in recent months

The announcement, made on the Treasury Department's website, is bound to ratchet up tensions between the US and its harshest critic in Latin America.

Mr El Aissami is the most senior Venezuelan official to ever be targeted by the US.

The US Government has also sanctioned Samark Lopez, a wealthy Venezuelan businessman believed to be Mr El Aissami's main front man.

As part of the action, 13 companies owned or controlled by Mr Lopez, including five in Florida, will be blocked and both men will be barred from entering the US.

There was no immediate reaction from Mr El Aissami, but he has long denied any criminal ties.

The move comes a week after a bipartisan group of 34 US lawmakers sent a letter to Mr Trump urging him to step up pressure on Venezuela's socialist Government by immediately sanctioning top officials responsible for corruption and human rights abuses, as well as Mr El Aissami for his purported ties to Hezbollah.

A long time coming

In the wake of President Nicolas Maduro's crackdown on dissent following anti-government protests in 2014, the US Congress passed legislation authorising the president to freeze the assets and ban visas for anyone accused of carrying out acts of violence or violating the human rights of those opposing Venezuela's government.

Monday's sanctions were imposed under rules passed during the Clinton administration allowing the US to go after the assets of anyone designated a drug kingpin.

Mr El Aissami, 42, has been the target of US law enforcement investigation for years, stemming from his days as interior minister when dozens of fraudulent Venezuelan passports ended up in the hands of people from the Middle East, including alleged members of Hezbollah.

Mass demonstrations were held against President Nicolas Maduro's Government last year. ( Reuters: Christian Veron )

Venezuela's top convicted drug trafficker, Walid Makled, before being sent back from Colombia in 2011, said he paid bribes through Mr El Aissami's brother to officials so they could turn a blind eye to cocaine shipments that have proliferated in Venezuela during the past two decades of socialist rule.

Mr El Aissami was named vice-president last month as Mr Maduro struggles to hold together a loose coalition of civilian leftist and military supporters whose loyalty to the revolution started by the late Hugo Chavez has frayed amid triple-digit inflation and severe food shortages.

Recent polls say more than 80 per cent of Venezuelans want Mr Maduro gone.