Tensions in Venezuela have escalated since Guaido, who heads Venezuela's National Assembly, declared himself acting president on January 23, a move which was supported by the US and many European and Latin American countries.
Maduro said on Tuesday he had spoken with military leaders and that they had shown him "their total loyalty".
Pompeo added that Washington had been told in recent weeks by "senior leaders" within the Venezuelan government that they would defect in the event of an uprising.
Pompeo said that the U.S. government was "committed to creating democracy here in the Western Hemisphere" and that Venezuela faced "the singularly worst humanitarian crisis, absent conflict, absent war, in the history of the world".
He urged "all of Venezuela" to protest on International Worker's Day, a globally celebrated holiday that falls on May 1.
Gunshots were heard at a rally led by Venezuelan opposition leader Juan Guaido outside a Caracas air base, Reuters witnesses said, after Guaido said earlier that troops had joined him to oust President Nicolas Maduro.
Cuba has stood by its ally Maduro and has denied USA accusations that it has military and intelligence operatives, which Washington estimates at 20,000 to 25,000 personnel - in Venezuela propping him up.
Protesters supporting both sides have gathered at different points in the capital, Caracas. Earlier this year, the United States banned the sale of Venezuela's oil in US markets, adding more financial pressure on the country.
Who is Venezuela's legitimate leader? "So if the military have the guns, they have the power and as long as Nicolás Maduro controls the military, he controls the country".
The Washington Post could not confirm who was driving the vehicles.
In the televised address, Maduro also made public the appointment of Gustavo Gonzalez Lopez as the head of the Sebin intelligence agency.
"That's right", Pompeo said.
As he and the president have emphasized repeatedly for months, Bolton said all options remain on the table when asked about the possibility of US military intervention.
"The opposition in Venezuela is fascist, they do not have the streets, they do not have support and that's why their only alternative is violence, coups", Gabriel Rodriguez, a singer and government supporter in Miraflores said.
Maduro's leftist Latin American allies Bolivia and Cuba also condemned Guaido.
The U.S. Federal Aviation Administration (FAA) on Tuesday evening issued an order prohibiting U.S. air operators from flying below 26,000 feet in Venezuela's airspace until further notice, citing "increasing political instability and tensions".
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