Pence, who arrived in Ecuador on Wednesday as part of a tour of South America, is seeking to boost regional pressure on Venezuela following Maduro's reelection in May in a vote that the United States said was fraudulent.
"Every time the poisonous viper Mike Pence opens his mouth, I feel stronger," the socialist leader said in a televised speech, according to Reuters. "We have defeated you and we are going to defeat (you) wherever you are."
Maduro insists that the United States is seeking to overthrow his government in order to seize the OPEC nation's oil and mineral wealth, and accuses Washington of leading an "economic war" against the country.
US President Donald Trump has imposed economic sanctions on Maduro and members of his cabinet on accusations they are undermining democracy and violating human rights.