Gaddafi asked: "How can we accept that a foreign power comes to topple an Arab leader while we stand watching?"
He said Saddam had once been an ally of Washington, "but they sold him out".
"Your turn is next," Gaddafi told the Arab officials gathered for the conference, some of whom looked stunned while others broke into laughter at his frankness.
In his speech, the Libyan leader also criticised Arab disunity and inaction on the region's multiple crises.
"Where is the Arabs' dignity, their future, their very existence? Everything has disappeared," he said.
"Our blood and our language may be one, but there is nothing that can unite us."
Gaddafi also mocked a plan by the Arab League to start Arab cooperation on a joint nuclear programme.
"How can we do that? We hate each other, we wish ill of each other and our intelligence services conspire against each other. We are our own enemy."
-Gaddafi condemns Arab leaders