The warning came amid reports of armed militias.
Deposed Venezuelan President Nicolás Maduro and his wife appeared in a federal court in New York City on Monday, following their capture by U.S. forces over the weekend in a military operation in the Venezuelan capital of Caracas.
Following the operation, President Donald Trump said that the U.S. would "run" Venezuela for an unspecified "period of time."
Venezuelan Vice President Delcy Rodriguez has been sworn in as interim leader to lead the country after what the Venezuelan Supreme Court described as Maduro's "kidnapping."
When asked by a reporter how long the U.S. plans on staying in Venezuela and how soon he would like the country to hold elections, Trump responded, "I'd like to do it quickly, but it takes a period of time."
The president cited infrastructure improvements, contending that it was "old, rotted."
Gen. Dan Caine, chairman of the Joint Chiefs of Staff, said the operation in Venezuela was known as Operation Absolute Resolve and involved more than 150 aircraft across the Western Hemisphere.
Caine said it was the "culmination of months of planning and rehearsal" adding that the operation could only have been conducted by the U.S. military.
"Maduro and his wife, both indicted, gave up and were taken into custody by the Department of Justice, assisted by our incredible U.S. military with professionalism and precision, with no loss of U.S. life," Caine said.
Trump was asked by a reporter who was running Venezuela now.
"Well, we're going to be running it with a group, and we're going to make sure it's run properly," he responded.
When asked about troops on the ground, the president said, "We're not afraid of boots on the ground."
Trump said he was going to designate some people as part of the plan but did not give any specifics.
"We're going to run the country right," Trump added.
Rubio spoke about the years of prosecution and international action against the Maduro government.
"I want to be clear about one thing, Nicolas Maduro had multiple opportunities to avoid this," he said. "He was provided multiple very, very, very generous offers, and chose instead to act like a wild man."
