The United States has threatened Venezuela with severe consequences unless President Nicolas Maduro immediately release a senior aide to Juan Guaido, who was snatched from his home by masked intelligence agents in the early hours of Thursday.

Roberto Marrero, chief of staff to Mr Guaido, shouted out loud that Mr Maduro’s agents had planted two rifles and a grenade on him, Mr Guaido tweeted. On Thursday afternoon, 12 hours later, Mr Marrero was still being held.

John Bolton, the US national security advisor, said that the arrest of Mr Marrero “would not go unanswered”.

“Maduro has made another big mistake,” he added.

Mike Pompeo, the secretary of state, also threatened to "hold accountable those involved".