Addressing the Venezuelan National Assembly on Sunday, Jackson called for the US Justice Department to investigate the statement by famous evangelist Pat Robertson, who last Monday said of Chavez: "I don't know about this doctrine of assassination, but if he thinks we're trying to assassinate him, I think that we really ought to go ahead and do it."
Jackson, on a three-day visit to Venezuela to meet Chavez, politicians and community leaders, also called on US President George Bush to express "a swift rejection" of Robertson's statement.
"It must be unequivocally clear that such a heinous act is not desirable nor designed nor planned. We must use power to reduce tensions, reduce the rhetoric of our threats," Jackson said.
"It was such a repugnant, immoral, illegal statement," he said.
Robertson apologised on Wednesday for his statement but then went on to compare Chavez to Saddam Hussein and to suggest the United States could one day be at war with his oil-rich country.
Chavez, a twice-elected leftist and close ally of Cuban President Fidel Castro, has often said Washington would like to assassinate him and accuses the Bush administration of involvement in a coup d'etat that toppled him for 47 hours in April 2002.
US officials last week distanced themselves from Robertson's comments.