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(CNN) US Secretary of State Mike Pompeo has denounced President Nicolas Maduro's obstruction of aid deliveries to Venezuela as the actions of a "sick tyrant." 

At the call of opposition leader and the nation's selfdeclared interim president, Juan Guaido, foreign aid has been shipped to Venezuela in response to worsening food and medicine shortages.

Maduro, who has been in a standoff with Guaido for the presidency, denies that a humanitarian crisis exists in Venezuela and suggests that aid efforts are part of a US plot to orchestrate a coup.

After Guaido named Saturday as the deadline for the aid to cross the border, Maduro vowed to stop the supplies from coming into the country. At a large rally in Caracas on Saturday, he dared the opposition to call for elections and called Guaido a "clown" and a "US puppet."

Trucks carrying supplies were blocked at most spots Saturday. Witnesses said two trucks were set ablaze while attempting to cross into Venezuela from Colombia.

Witnesses who spoke to CNN said the trucks went up in flames as Venezuelan troops loyal to Maduro prevented the vehicles from crossing the border. CNN cannot independently confirm the incident or the circumstances of how the two trucks were set on fire. National Assembly Representative and Guaido supporter Adriana Pichardo told CNN that at least five people were also killed in clashes with Venezuelan security forces on Saturday. CNN cannot independently confirm the number of fatalities.

Adapted from: https://edition.cnn.com/2019/02/24/americas/venezuela-pompeo-maduro-colombia/index.html. Acesso em: 24 de fevereiro de 2019.