US diplomats are visiting several African countries to urge leaders to press Kadhafi to leave power immediately, officials in Washington said, while the EU slapped new economic sanctions on Gaddafi's regime.
Libyan television showed footage of Gaddafi's youngest son, Khamis, supposedly visiting victims of NATO raids on Tuesday. But a rebel spokesman insisted that the 28-year-old, a feared military commander, was dead.
The date of the recording could not be confirmed. If genuine, it would be the first time Khamis had been seen in public since Friday, when rebels said a NATO strike on the western town of Zliten killed 32 people, including Khamis.
Gaddafi spokesman Mussa Ibrahim said at the time the claim was untrue, claiming it was "dirty lies to cover the murder of civilians" in Zliten.
Khamis trained at a Russian military academy and commands the eponymous and much-feared Khamis Brigade, one of the regime's toughest fighting units.
Reacting to the television report, rebel spokesman Abudulah Kabir said in the city of Misrata that the insurgents were sure Khamis was dead.
"The military council has confirmed he has died; we are sure," he said.
Fresh fighting erupted snech4nat the strategic oil town of Brega, an AFP correspondent said.
Mortar rounds and rockets struck intermittently on both sides of the front at Brega, one of the three main focuses in the Libyan conflict, with the other two at the enclave of Misrata to the east and the Nafusa mountains to the west.