Muammar Gaddafi has declared in an audio message that he was beyond the reach of NATO bombs, following a government denial of an Italian claim that the Libyan leader was wounded and on the run.
"I want to say to the Crusader cowards that I live in a place where I cannot be reached or killed; I live in the hearts of millions," Gaddafi said in the message broadcast on state television on Friday.
A series of six loud explosions rocked Tripoli late on Friday and early on Saturday as jets flew overhead. Smoke could be seen rising from one of the sites in eastern Tripoli, witnesses said.
Air raids have rocked the Libyan capital almost nightly, stepping up the pressure on the Gaddafi regime.
In Washington, the Libyan rebel movement's number two, Mahmud Jibril, was received at the White House by President Barack Obama's national security advisor.
The White House said the rebels' National Transitional Council was a "legitimate and credible" voice of the Libyan people. But it stopped short of offering the full diplomatic recognition that Jibril was seeking.
Questions about Gaddafi's fate arose earlier yesterday when Italian foreign minister Franco Frattini said Gaddafi was "probably outside of Tripoli and probably also injured."
He said the reports that Gaddafi was on the run were credible because they came from the Roman Catholic bishop of Tripoli. But the bishop, Giovanni Martinelli, later denied having made any such comment to Frattini.
"What the foreign minister said is not right because I never said that the Libyan leader was wounded," Martinelli told Radio France Internationale.
"I only said that he was under psychological shock from the death of his son. I did not say he was wounded or that he left Tripoli."
Libyan government spokesman Mussa Ibrahim told journalists in the capital that Gaddafi "is in very good health, high morale, high spirits," and "he is in Tripoli."
Gaddafi's audio message appeared to have been made sometime after a NATO strike on his Bab al-Aziziya compound early Thursday, because Gaddafi referred to its having "led to the martyrdom of three civilians, journalists."