The US state department has dismissed claims by Venezuelan President Hugo Chavez that Washington is planning to kill him as "ridiculous and untrue".
Hugo Chavez: "I know that I have been condemned to die"
"The idea that we were out to get the president of Venezuela is just plain wrong," spokesman Richard Boucher said.
Mr Chavez made the allegation on Sunday during his weekly TV show, although he gave no evidence to back it up.
He said any attempt on his life would backfire and threatened to cut off oil supplies to the US.
"If they kill me, the name of the person responsible is [President] George Bush," Mr Chavez said.
"If, by the hand of the devil, those perverse plans succeed... forget about Venezuelan oil, Mr Bush," he added.
He was apparently reacting to growing criticism by top US officials of his left-wing government.
US Secretary of State Condoleezza Rice has recently described the former paratrooper as a "negative force" in Latin America, while CIA chief Porter Goss said Venezuela was a possible source of instability in the region.
Washington accuses Mr Chavez of being heavy-handed towards Venezuela's opposition, and has recently criticised Caracas for arms purchases from Russia.
Mr Boucher told reporters that the US wanted to look at "various policy issues that we have with the government of Venezuela".
"We have to be concerned about these aspects of Venezuelan behaviour because they are disruptive to the region and we need to address them," he said.
Rice and other US officials have recently stepped up their criticism
Venezuela is one of the world's leading oil exporters - it sells about 1.5 million barrels a day to the US.
Diplomatic ties between Washington and Caracas have soured since Mr Chavez came to power in 1999.
Mr Chavez has repeatedly accused the US of backing Venezuela's opposition to oust or even kill him, a charge Washington denies.
He has alleged that the White House played a part in the April 2002 coup which briefly removed him from power.
Mr Chavez's comments echoed the words of Cuban President Fidel Castro who said last week: "If Chavez is assassinated, the blame will fall on Bush."