"Eight senior officers who defected from Col Muammar Gaddafi's army have appealed to fellow soldiers to join them in backing the rebels.
One of the eight accused pro-Gaddafi forces of "genocide".
The men - who are said to include five generals - appeared at a news conference in Rome.
One of the generals who spoke to reporters in Rome, named as Oun Ali Oun, read an appeal to fellow soldiers and security officials to abandon the regime "in the name of the martyrs who have fallen in the defence of freedom".
He also denounced both "genocide" and "violence against women in various Libyan cities"
Another general, Melud Massoud Halasa, told reporters that Col Gaddafi's forces were "only 20% as effective" as they were before the rebellion, as "not more than 10" generals remained loyal to him.
Former Libyan Foreign Minister Abdel Rahman Shalgam, who now backs the rebels and appeared at the news conference, said a total of 120 soldiers had defected in recent days.
Since the start of the uprising in February dozens of army officers, government ministers, and diplomats have abandoned Col Gaddafi."