Seif al-Islam Gadhafi, in the regime's first comments on the six days of demonstrations, warned the protesters that they risked igniting a civil war in which Libya's oil wealth "will be burned."
The speech followed a fierce crackdown by security forces who fired on thousands of demonstrators and funeral marchers in the eastern city of Benghazi in a bloody cycle of violence that killed 60 people on Sunday alone, according to a doctor in one city hospital. Since the six days of unrest began, more than 200 people have been killed, according to medical officials, human rights groups and exiled dissidents.
Lybia's response has been the harshest of any Arab country that has been wracked by the protests that toppled long-serving leaders in neighboring Tunisia and Egypt. But Gadhafi's son said his father would prevail.
"We are not Tunisia and Egypt," the younger Gadhafi said. "Moammar Gadhafi, our leader, is leading the battle in Tripoli, and we are with him."
"The armed forces are with him. Tens of thousands are heading here to be with him. We will fight until the last man, the last woman, the last bullet," he said in a rambling and sometimes confused speech of nearly 40 minutes.
The younger Gadhafi, who is the regime's face of reform, conceded that the army made some mistakes during the protests because the troops were not trained to deal with demonstrators, but he added that the number of dead had been exaggerated, giving a death toll of 84.
Western countries have expressed concern at the rising violence against demonstrators in Libya. British Foreign Secretary William Hague said he spoke to Seif al-Islam Gadhafi by phone and told him that the country must embark on "dialogue and implement reforms," the Foreign Office said.
In the speech, the younger Gadhafi offered to put forward reforms within days that he described as a "historic national initiative" and said the regime was willing to remove some restrictions and begin discussions for a constitution. He offered to change a number of laws, including those covering the media and the penal code.
Protesters had seized some military bases, tanks and other weapons, he said, blaming Islamists, the media, thugs, drunks and drug abusers, foreigners - including Egyptians and Tunisians.
He also admitted that the unrest had spread to Tripoli, with people firing in central Green Square before fleeing.