CARACAS, Venezuela — President Chavez of Venezuela said Sunday that he has received warnings from within the White House that the Bush administration is plotting to assassinate him or topple his left-leaning government.

Citing what he said were warnings from an alleged White House informant, Mr. Chavez told thousands of supporters at a campaign rally that President Bush has ordered him to be killed before he leaves office in 2008.

Mr. Bush “has said that before he goes, Hugo Chavez shouldn’t be the president of Venezuela,” Mr. Chavez told the crowd. “The president of the United States has said it, especially in recent days. What he doesn’t know is that I have friends in the White House.”

The democratically elected Venezuelan leader has said before that the American government is out to kill him — allegations that American officials have denied. The latest accusation came a day after he alleged that someone had recently attempted to assassinate him. He said those responsible had since fled to neighboring Colombia.

Mr. Chavez appeared to link the alleged plot to his main rival in upcoming presidential elections, Governor Manuel Rosales of Zulia state, claiming that he is in constant danger from opponents seeking to get rid of him.