US increases pressure on Maduro administration after detention of Guaido aide

U.S. President Donald Trump's national security adviser called for the immediate release of Venezuelan opposition leader Juan Guaido's chief of staff on Thursday, saying his detention would "not go unanswered."

White House national security adviser John Bolton said the government of Nicolas Maduro had "made another big mistake" with the "illegitimate arrest" of the aide, Roberto Marrero. "He should be released immediately and his safety guaranteed," Bolton wrote in a Twitter post.