Sen. Rick Scott, R-Fla., wants the U.S. Navy to block Cuba and Venezuela's oil trade.
Cuba has been aiding Venezuelan President Nicolas Maduro, who last week survived a brief military uprising.
The U.S. is backing Venezuelan opposition leader Juan Guaidó, who launched Operacion Libertad, an attempt to topple Maduro.
"It's clear that the United States needs to consider using naval assets to block the flow of oil between the two dictatorships," Scott said in a statement Wednesday. "The president has floated the idea of a full embargo on Cuba. I agree with him wholeheartedly. We need to take action NOW to capitalize on Maduro's weakness and end his brutal regime. Cut off Cuba, and you cut off the political forces supporting genocide in Venezuela."
Guaidó has been trying to oust Maduro since Jan. 23. The U.S. and more than 50 other nations now recognize Guaidó as Venezuela's leader and have threatened severe measures against the regime if he were harmed or arrested.
President Donald Trump last week threatened a full embargo against Cuba, alleging it was providing him with economic and military aid.