US President Donald Trump's national security advisor warned Tuesday of “serious consequences” if any harm comes to Venezuelan opposition leader Juan Guaido.

“Let me reiterate — there will be serious consequences for those who attempt to subvert democracy and harm Guaido,” Trump advisor John Bolton tweeted.

Washington has recognised Guaido as the South American country's acting president and says that strongman President Nicolas Maduro should leave power.

Editorial: Venezuela turmoil

Bolton's warning followed a request by the Maduro government's attorney general for the Supreme Court to bar Guaido from leaving the country and to freeze his assets.

That followed the United States' decision to hand control of Venezuela's US bank accounts to Guaido, barring Maduro from accessing the funds.

Guaido said on Monday that the US maneuver would stop Maduro from emptying the “coffers” if he is removed from office.